I read Ask Metafilter twice daily. I contribute far less frequently, and I skip a lot of threads—the site has too many discussions about computer problems and places to drink in New York City—but the sheer breadth of questions is fantastic, especially now that the site has re-introduced anonymous asking.
A sampling from the past 24 hours alone:
With this level of diversity and sheer randomness, it’s a must-visit.
I’m also an Ask Metafilter user. Here are the questions I’ve asked over the years, which I think are a pretty good introduction to the site on their own.