If you're in New York tomorrow and like vodka, you can drink for free for 90 minutes — no pacing yourself! — at the "Bloody Mary Mixer," an event sponsored by "Takes All Types," a non-profit organization that's trying to make blood donation smarter. Sign up for their Facebook app — it'll add a blood type card to your profile, just like you're a Japanese fighting game star. Better, when there is a need for your blood type in your area, you can get an alert via Facebook, email, or SMS.
Disclaimer: I had a beer with these guys last week which I think maybe makes me an advisor or something.