The Freakonomics geeks analyze this year's incentive at the upper west sider generated Joel Kishner Memorial Blood Drive which is all put together by Jill Strauzer's charitable Angels in Waiting network. (Which happens to be the biggest mobile blood drive to date in NY dedicated to a young observant west sider who died suddenly)
Last year Ben and Jerry's Ice Cream gave out a pint for a pint (ice cream thicker than blood) at the drive. This year, aside from Ben and Jerry getting back in on it, Reebok Sports Club (the gym Seinfeld goes to) was going to give you a day pass with your donation. The problem is, so says the NY Blood Center CEO, its worth too much money and against the law.
Luckily West Side genius and blood drive chair, Jeff Stier, (who is actually a real blogger on Huffington Post)came up with a teshuva that even the Freakonmies liked. Check it here