Rayman's Indrediballs is a very fun FRIV type IO game. Land your avatar on a board and use the arrow keys to move around and dodge other players and hazards such as fireballs and carnivorous plants. Collect lives, a protective shield or boxing gloves to beat the other players. Don't fall into the holes and revive to keep playing. The board gets smaller as there are fewer players, so the complexity of moving fast and dodging danger increases.