It's Always Sunny is based around a group of four friends who own a bar in Philadelphia, but it's not a cookie-cutter sitcom at all.
Dee, Charlie, Dennis and Mac (and Frank) are a gang of narcissistic, egotistical, self-absorbed, backstabbing tools and they're a pleasure to watch. It's Always Sunny is not for the easily offended but any show that deals with racism, abortion, cancer and molestation in the first season gets my vote.
A+ and I can't wait for the next few seasons to come out on DVD.