What I really like about this is that you pay to play, but you can easily practice the game without playing. That means you can develop some expertise first, and then try your hand at being lucky or good.

QUOTE
After months of debugging, a Texas economist-turned-entrepreneur has taken the wraps off SpaceShot, an online weather-prediction game that offers flights to the edge of outer space as the top prizes.
...
Here's how the game works: For $3.50 a play, users lay down their predictions for the next day's weather in New York's Central Park, as recorded by the National Weather Service: high and low temperature, precipitation and humidity.


MSNBC

The side benefits include people learning a bit about meteorology.

Is it work risking a few hundred dollars to get to space? Didn't we just have a thread on gambling?