Algodoo

Ping Pong with simple AI player
Red is you (up /down keys)
Blue is AI
AI reacts to the movement of the ball
so it is not really smart but it can beat you
to start copy the ball into the field an push it a bit
r - reset score
if the speed increases to fast for you, modificate the restitution of the players (now = 1.2)
there is no long script or anything like that ,so dont expect too much