Have you read my post about how much I like Ebates? Ebates pays you to shop online, so it's easy to save 5%+ buying things that you would normally buy anyway!
Their referral program is really good, but right now it's even better with a $30 cash reward if you refer 3 friends by 08/31/11. Plus, your referred friend can choose from a few different $10 gift cards just for signing on! Such a great deal for both people involved!
If you don't know much about how Ebates works, you can read their FAQ here.