Economics: Bryan Caplan has some good blog posts and an interesting looking book called The Myth of the Rational Voter.
Fun: Bay Area Ski Bus.
Self Improvement: Stickk helps you achieve your personal goals by using real economic incentives to guide your decisions.
Software: A great review of free CD and DVD burning software.
Startups: Help build a startup in 48 hours.
Travel: According to Lessno, late Thursday night is a good time to check for the best deals."