If you're not using Twitter, you should, if only to follow some very funny/interesting people. Here is my Top Ten list of best geeks to follow on Twitter:
10: @BigBoyler (Chris O'Dowd from "The IT Crowd"): O'Dowd's off-kilter non sequiturs are always good for a laugh.
9: @michaeljnelson (Mike Nelson from "MST3K" and RiffTrax): Nelson doesn't tweet as often as some, but when he does, it's always funny. It's also worth it to follow his conversations with fellow riffers Bill Corbett and Kevin Murphy.
8. @kwmurphy (Kevin Murphy): Murphy is funny and very in touch with his fans. He and Corbett also have an awesome rapport, which makes it worth to follow him to keep up with their conversations.
7. @BillCorbett (Bill Corbett): Corbett is the most frequent tweeter of the "MST3K" guys and like Murphy, is responsive to his fans. He's funny and manages to retweet funny things from his followers
6: @ConanOBrien (Conan O'Brien): O'Brien took to his Twitter account after his contentious departure from NBC prohibited him from immediately returning to television. His tweets are always concise and funny, acting like a peek inside his very quirky brain.
5. @donttrythis (Adam Savage from "Mythbusters"): Savage tweets a balanced combination of anecdotes on his life, his work on the show, and funny non sequiturs.
4. @nickjfrost (British comic actor Nick Frost, famous for his role as Ed in Shaun of the Dead): Frost's irreverent tweets and frequent joshing with friend and costar Simon Pegg make following him feel like part of their inner circle.
3. @simonpegg (star of Shaun of the Dead): Pegg gives you an inside look at his life and his friendship with Frost. He frequently tweets pictures, which increases the feel of familiarity.
2. @thinkgeek (geektacular online store): Clever employees (or "monkeys") of the awesome website tweet funny tidbits along with news about the site and upcoming deals. Following @thinkgeek is a guaranteed reciprocal follow and they are very responsive to fans/customers.
1. @wilw ("Star Trek" alum and founder of geek fest Wootstock Wil Wheaton): Wheaton's tweets are equal parts anecdotes about his life, geeky musings, and spirited conversations with his followers. My personal favorites are his amusing conversations with his perpetually apathetic cat.