Even though he sometimes uses language that would make my mother faint, Louis CK is one of my favorite comedians. (And the part about my mom is no exaggeration. My brother Steven is a huge Howie Mandel fan (yes, apparently there is such a thing) and for his birthday he wanted to go see Howie perform but when Mr. Deal-Or-No-Deal started dropping the swears my mom freaked out and wanted to leave but Steven wanted to stay. So she covered her ears and successfully blocked the evening from her memory.)
You may have seen one of Louis CK's comedy specials on Comedy Central or noticed him as Amy Pohler's cop love interest on Parks and Recreation. Hilarious, is a two-hour performance movie by Louis CK. It was really funny but I wouldn't recommend it if you have delicate sensibilities (This means you, Mom!).
The best part of the viewing was that Louis CK was there in person! He introduced the film and then held a lengthy Q&A session afterward. It was fun to see him in person. He definitely had a self-loathing vibe roiling off him (surprise, surprise) but he was very nice. I was tempted to ask to take a picture with him but decided it would be tacky; he looked really tired by the end of the Q&A.
Louis CK did a bit on Conan's show that's been making the rounds on the ol' internets. It's pretty great (and swear-free since it was on network tv). He included a longer version of it in the movie. Check it out.