This is a contest started by mathgrant on his blog here. It is an innovative contest where you can donate to 3 particular charities Grant has partnered with, and your donations will earn you a given number of entries into a prize raffle of the particular charity you choose. Grant has also mentioned he will upload huge puzzles each time the donation amount crosses a landmark.

The charities are -
1. Sanctuary Home for Children
2. Child's Play Charity
3. Jack Vasel Memorial Fund