Recommended games:
Sudoku Afinic
Multiplayer(versus & cooperative) and single player sudoku.
Come2Play Multiplayer Games
These are Multiplayer flash board games: Chees, Backgammon, Reversi, Connect 4, TicTacToe, Checkers and more.
The ad is shown at the beginning of each game (when you choose to play)
Mahjong Sudoku
Sudoku combined with Mahjong. Instead of numbers you need to place Mahjong stones with 1-9 dots.
Falling Sudoku
Combination of Falling Blocks Game and Sudoku. Solve the sudoku while the numbers are falling down.