Today's Wednesday Factoid is: Have you ever collected box tops for a program (or anything similar)?
Hm, when I was a kid I think I collected some kind of cereal points for some reason, but I don't even remember what the program was. I did collect some box tops for an offer to get a stopwatch, that's not really the same as what this question is asking, I don't think.
The closest I can think of is that I collect bottle caps from Coke products and I enter the codes into a website so I can redeem the points for a variety of gifts in a catalog. Mostly I just turn them in for bookstore gift certificates. It's pretty nice (even though it's a little annoying to plug those codes in), because if you're going to be drinking the soda anyway you might as well get some free stuff if they're offering it!