We've had topics posted in the past about various websites where you can earn some extra cash or other rewards. Yan created a nice wiki at http://www.buxr.com/wiki/money_making_sites
that lists all the sites we know about, all on one page together. Check it out to see all the choices, the list is always growing!
Please add any new sites you find, or let us know in the comments here. Also, give us some feedback if you've tried any of them.