Each player chooses a number between 0 and 100. Each player's payoff will be twice the minimal of the two numbers minus the number that they themselves have chosen.
This game has one payoff dominant equilibrium where both players choose 100, one equilibrium where both player choose 0, and 99 symmetric equilibria in between where always both players choose the same integer.
Here is the Implementation. You have to open it in two new windows to be able to play. To compile your own version you need the cgihtml library and the sources shown below.