Everyone seems to be offering these things on blogs (although I've also seen them advertised at $10 a pop while exploring the idea of setting up an "exchange" site), and I have six of'em. So, here's how it works:
The first six people to leave a comment asking for one and including an email address get a Gmail invite.
Hint: If you are comment #7 or later, don't bother. When I have more invites, I'll post'em, not come looking back at this post. As a matter of fact, I'll probably delete the post when the six are given out.