Generally I don't go for referral offers, but I know three people who just got a Free Mac Mini this week by using this site, so it's legit and each person only has to sign up for a single offer. I used the Stamps.com offer which gives me $5 free internet postage - I was thinking of trying them anyway so no big deal.
Anyway, I figured if anyone wanted to try it I'd post my referral link. If you go through and don't see any offers you're genuinely interested in then by all means just walk away. But if you can remember to cancel an offer within 30 days (your offer credit goes through in a little under a week on the free mac mini site, so any time after that is fair game to cancel) and you can get ten other people to join and complete one offer apiece to get your Mini (and they'll get one, etc.) then give it a go. I haven't received any extra spam due to this offer (although I did use my Gmail account to sign up, just in case).
I've been dying to get a Mac to develop with, but I can't afford one, so this is a decent opportunity to get one to mess around with. They're really tiny and surprisingly fast for the 1.47Ghz processor (the give-away is the 80Gb model with the fastest processor).
Here's my referral link: