akline,
You join MyPoints.com and shop through their site, sometimes they have surveys, and they send out bonus emails worth 5 or 10 points for clicking on the link.
You can cash them in for a number of things--mostly gift certificates for places like Rainforest, Barnes&Noble, JCPenney, etc. There are also gas cards. And most of the people here cash out for what we call Webbies from Webcertificates.com. You then set up an account with Webcertificates and get a number that can be used anywhere MasterCard is accepted. It's a debit account. You can also pay them $6.95 to get a plastic card that you can use in the "real world" anywhere you would use a MasterCard. Lots of people do this and buy Disney Dollars with them. Some people have had luck just printing out their account info and getting the cast member to punch in their number.
HTH!