Lets see... ask a question - if its good... you get THREE upvotes... and you can upvote. Or, you can post ONE good answer, and have it voted up, just TWICE, or get it right... and you're there.
Or if you already have an account elsewhere, and you link it, you get 100 rep!
Isn't that hard to get 15 rep. Getting that rep, basically means you've bothered to make an effort, and have contributed to the site.