Ricochet is a very simple game - in fact, mostly a logic puzzle/math challenge. However, it is presented in a format that makes it into a game and great fun to play. In order to appreciate the game properly, you need to find a group of players that enjoy a mental challenge and who do not mind the competitive or time pressure element of the game - with that, the game is pure brilliance.
A fast reaction game where your eyes bounce from card to card trying to figure out what the final solution is. I love these type of reaction games where everyone is simultaneously trying to be first to come up with the answer.