Planet Money has a terrific new episode on the allocation of slots in the NYC marathon [link].
So there's roughly 50k slots and 150k applicants. More applicants than slots. How to allocate this fairly? Apparently, the NYC marathon has 4 ways you can get in:
1. lottery -- completely randomized, one entry per person
2. merit -- run below a certain time in another marathon
3. desire (money) -- they give away slots to charities who then...