If you don't know Stumble, you're missing out. Here's a list of extremely useful sites I found while Stumbling this past week:
Librarian Chick: This is a list of free resources for students and educators, although I am neither and I see all sorts of ways to keep myself occupied. I strongly suggest checking this out before you go hunting for information or paying for solutions that may not be necessary. This is definitely a launching pad to hundreds of incredibly useful websites
DefenseLink Blogger's Roundtable: Depending on which side of the political fence you sit, this is either propaganda or a legitimate way for the Department of Defense to get their story out to bloggers. Don't expect to get objective stories - that isn't the purpose of the site. It's also a jumping-off point to all sorts of data of interest to Aerospace & Defense market research analysts (like I used to be) - in 3 clicks, I downloaded a 3,000+ page report showing every contractor that received a DoD contract in excess of $25K in FY2006, organized by place of performance. If you've got a lot of time on your hands, you can map this against congressional districts and see which legislator does the best job bringing home the bacon. But, there's probably a database with that someplace (note to self - find that sucker!).
American Rhetoric: Top 100 Speeches of the 20th Century: MLK, JFK, FDR, and a host of others are well-represented, for when you need a little inspiration, perhaps a few quotes, or want to introduce your kids to the great events and people of the 20th century.
Penny Alcohol Backpacking Stove: Hey, I said "Useful", not "Deep Thoughts". If you're into hiking or camping and like to build lightweight gear, or you've got a boy scout in the family and want a rainy-day project, this would be a cool one to try.
2008 Presidential Election Candidates on the Issues: A matrix showing the position each candidate has taken on the major issues of the day.