As we prepare to ring in a new year, RadarOnline.com takes a look back at the celebrities we lost in 2011 who made their memorable mark on the world.

Apple founder Steve Jobs died at 56 on October 5 after a long battle with pancreatic cancer. The tech guru leaves a vast legacy in his industry over the better part of four decades, listed as the inventor of household items such as iPod, iPhone and iPad, among others. He was also the driving force behind companies like Pixar and Atari.

Legendary newsman Andy Rooney died November 4, just weeks after his 1097th and final weekly segment on the CBS stalwart 60 Minutes, capping off a 33-year run.

PHOTOS: Celebrities We Lost In 2011

Surprisingly, the most shocking comment at Charlie Sheen's Comedy Central Roast on Monday night wasn't about hookers, blow or boozing  - or even about Charlie Sheen himself!

Comedian Amy Schumer managed to jack the distasteful factor up a giant notch with a controversial joke about deceased Jackass star Ryan Dunn that went down like a lead balloon with his best friend Steve-O, but despite the backlash, the little-known comic exclusively told RadarOnline.com that she has no regrets.

"If anyone feels offended then they are justified but I don’t think it was out of line. It was not my intention to offend but I stand by my joke," Schumer said. "It’s a roast and we’re going for the jugular. It was a joke about Steve-O and not about Ryan," she went on to explain. "I hope people understand that."

Is it possible to go too far at a roast?

Relatively unknown comic Amy Schumer put the question to a test in her set at Charlie Sheen's Comedy Central roast that aired Monday, using the recent death of Jackass star Ryan Dunn as grist for the comedic mill while taking a shot at one of the celebrity roasters on the dais, Steve-O.

After sending condolences to Steve-O, Schumer said, "When Ryan Dunn died Steve-O probably was thinking it could've been him ... with the rest of the world wondering, ‘Why wasn't it?’” (An upset Steve-O kept a blank expression after the joke was told.)

Dunn, 34, died in June, along with a passenger Zachary Hartwell, 30, after a fiery crash in West Chester, Pennsylvania. Authorities later declared Dunn had a blood alcohol level of 0.196 percent, more than twice the Pennsylvania legal limit of 0.08.

Johnny Knoxville has taken to his blog to write about the loss of his Jackass co-star and close friend, Ryan Dunn.

Knoxville confessed that he had been unable to express his feelings adequately at Dunn's memorial last Wednesday, admitting that he "tried to share memories of my dear friend, but the words were just spinning in my head. What came out were the mumblings of a man trying his best not to cry, and I wasn't even successful at that."

So, the 40-year-old father of two has written a moving account of his deceased friend, detailing Dunn's humor, kindness and capacity to love.

Guests Arrive To Ryan Dunn Memorial

"I felt 34-percent funnier when I was with Ryan, but I guess everyone did. He had such a hair trigger laugh reflex," Knoxville writes. "He lived his life wanting to laugh and wanting you to laugh with him. He would cackle really fu**ing loud, too, and it wasn't uncommon that he would fall over from it. Sometimes I would fall with him because his spirit was very contagious.

"He wasn't incapable of seriousness, though. Ryan was a great listener. If you were having troubles, he was always someone you could go sit down and talk to. Granted, most of our sitting down was actually standing up playing pool together, but he was always there if you were sad about something. That's why all this is even harder because right now I really need to talk to him but I can't.

"Ryan also had an enormous capacity to love. His friends and family got a lot, but a lion's share of that went to his sweet and beautiful Angie. If he wasn't with her he would be talking about her. More times than not he would smile wide through that filthy ass beard of his and say something along the lines of, "How did I ever luck up and land her?" Well, it sure wasn't because of the way he smelled that's for sure. (Dunn despised water and rarely bathed.) It was because he had a pure, open heart, and many other qualities of which I am writing about now."

Jackass Star Ryan Dunn – Through The Years

Knoxville goes on to say how difficult it was to wake-up his daughter Madison and tell her Dunn was gone and how upset he is that his young son, Rocco and soon to be born daughter will never know him.

Knoxville finishes: "I'm hurting!! We all are because we loved you so much and now you're gone. I know your spirit lives on in me, Angie, Bam and everyone you touched, but that's pretty tough to see right now through the tears. I'm starting to ramble now, just like I did at the memorial, so I'll stop. You'll have to excuse me, I'm just very sad because I lost my brother and my world got about 134-percent less funny. I don't know what else to say right now, so I will close with I love you, Ryan. I have a lot of emotions swirling, but I want you to know I love you so very much."

As RadarOnline.com previously reported Dunn died in a horrific car crash in the early hours of Monday morning. Police revealed that he was estimated to be driving at around 140mph and that his blood alcohol level was almost two-and-a-half times the legal limit. Dunn's passenger, Zachery Hartwell, an Iraqi war vet also died.

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The week started on a tragic note when Jackass star Ryan Dunn died in a fiery car crash in Pennsylvania, and his friends and family commemorated his life in a tearful memorial.

It was wedding bells for 16-year-old Courtney Stodden as she walked down the aisle with 51-year-old Green Mile star, Doug Hutchison in Las Vegas.

Tobey Maguire didn't have a poker face when he found out he was getting sued over alleged multi-million dollar poker game payments from Brad Ruderman, a hedge fund manager who ran a Ponzi scheme.

Hollywood's favorite jailbird Lindsay Lohan was back in court after a dirty alcohol test but the judge found her not guilty of violating her parole and released her back into house arrest.

The gangster who inspired hit movie The Departed was finally behind bars as America's Most Wanted criminal James 'Whitey' Bulger was arrested in Santa Monica after 16 years on the run from the FBI.

She's fond of flashing flesh, but Jennifer Lopez let a little too much hang out when she had a wardrobe malfunction and had a nipple slip on German television.

Runaway bride Crystal Harris spent what should have been her wedding day to Playboy boss Hugh Hefner partying in Las Vegas with Heidi Montag.

There is a whole lot less of Kirstie Alley to watch nowadays as she showed off her mammoth 90 pound Dancing With The Stars weight loss on The View.

Beloved Columbo star Peter Falk passed away at the age of 83 after suffering from Alzheimer's disease for many years.

The drama mounted in the Casey Anthony murder trial as her mother and brother both broke down on the stand giving emotional testimony.

Arnold Schwarzenegger spent Father's Day with his son Christopher and RadarOnline.com revealed that he is paying child support to Maria Shriver despite neither party having officially filed for divorce yet.

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Police investigators believe that fans of Jackass star Ryan Dunn may have unwittingly bought him drinks that contributed to his fatal car crash, RadarOnline.com can reveal.

Dunn and co-passenger Zachary Hartwell were killed instantly when the madcap actor lost control of his Porsche 911 at speeds of around 140mph while being twice over the legal limit.

West Chester State Police Liquor Control Enforcement Sgt. William La Torre now believes that fans gave Dunn drinks in a secluded area of an outside patio at Barnaby’s Of America bar in West Chester, Pennsylvania, before he got into his sports car.

A non-profit drunk driving awareness organization is asking Bam Margera to record a public service announcement denouncing drinking and driving, just days after his Jackass co-star and longtime pal Ryan Dunn died in a fiery, alcohol-related crash.

DrinkingandDriving.org president Allen Porter exclusively provided RadarOnline.com with the letter he sent Margera, urging the popular TV personality to use his influence to take a stand against the dangerous practice that killed both Dunn and his passenger, Iraq war veteran Zachary Hartwell.

EXCLUSIVE DOCUMENT: Anti Drunk Driving Group Reach Out To Bam Margera

Jackass co-stars Bam Margera and Johnny Knoxville mourned the loss of Ryan Dunn on Wednesday during a private memorial service.

Friends and family gathered at a West Chester, Penn. funeral home on Wednesday to pay homage to their fallen friend.

PHOTOS: Guests Arrive To Ryan Dunn Memorial

Margera’s parents, Phil and April, who also appear in the Jackass franchise were there as well. “I felt like I lost one of my own sons when I heard that Ryan Dunn died,” April told RadarOnline.com the day of his death.

Jason "Wee Man" Acuna has memorialized his fallen Jackass colleague Ryan Dunn by getting an image of Dunn's face tattooed on his leg.

"How can I do something for Ryan?" Wee Man says in a video, prior to getting inked. "Well, it's something he'd probably do for anyone of us if it was one of us in the situation.

PHOTOS: Jackass Star Ryan Dunn – Through The Years

"And I'm going to get him tattooed on me. Yes, that's what I'm gonna do."