There are a number of online bank accounts that will offer you $20-$50 for opening an account. There are also credit cards that offer money from time to time; there's currently an offer for a citibank amex with $100 for using the account.

I'm going even further along that, I find a credit card offer with a no fee 0% interest balance transfer, I transfer all of my regular monthly charges on to it, and I park the money in a high yield savings account. If the thought of that doesn't make you queesy it's not a bad way to make several hundred dollars over a year.