Craig's List - Free daily job listings in major cities
Backdoor Jobs - Listing of a lot of temporary outdoors-type jobs
National Park Service Temporary Employment (U.S.A.)
Cafe Press - Create your own shiz
Dave's ESL Cafe - If you have a Bachelor's degree , there are a myriad of English teaching opportunities overseas , or so they tell me. I don't have one , so I'm stuck here :)
Medical Transcription - I've been kicking this around as an idea. I imagine it would be pretty tedious , but can be done entirely via telecommuting on your own schedule. Something to think about.
Americorps - If you're in the U.S. , interested in public service and don't mind working for the government this might be something to get into for awhile. I don't know a whole lot about it personally.
Summer Camp Jobs - There are a thousand of these types of sites , I dunno if this one is better or worse than most , it's just the first result I got from Google. Instead of creating a giant index of them I just put this one here as an example. Google the phrase to find many more.
Find a Job in Antarctica - apparently there's a lot more competition than you might think