Sure, there are a few scifi comedies out there we all agree are great — Third Rock from the Sun comes to mind, as well as the ever-awesome Galaxy Quest. Still, there is only so much SF comedy. What about comedies that aren't specifically science fiction but are still beloved by SF fans, like Community and Monty Python?
What would you recommend to your fellow SF fans when they are looking for some good comedy? My recommendation of the day is the Canadian show Trailer Park Boys (see clip). Even though it has nothing to do with SF, this series about small-time criminals in a Halifax trailer park has a surprising amount of geeky humor, and is incredibly well written. Pay attention - the jokes may seem crass, but they're also pretty subtle too. Plus, the character Bubbles is my favorite trailer park nerd ever.
Tell everybody in comments what you'd recommend!