NIM-Logic
How Close to 100?/How Close to 400?-Multiplication
Salute-Multiplication
3-5 Math For Love Games
The link below has several games designed for 3-5 students. The games that I particularly recommend are:
Don't Break the Bank-Triple Digit Addition/Estimation
Fives and Tens-Multiplying by fives and tens/Place Value
Hex Rules-Strategy/Spatial
Horseshoes-Estimation/Four Operations
Multiplication Table Tic-Tac-Toe-Multiplication Facts