To date, two puzzles have been revealed, though others may lie dormant.

The first puzzle was revealed in post 16, which contains all the hints you get (: The second puzzle was revealed in post 25. Mysterious prizes await winners, and for each puzzle, the first 5 get their names on the leaderboard for all time:

Puzzle 1

First
Second
Third
Fourth
Fifth

Puzzle 2

First
Second
Third
Fourth
Fifth