Continuity mistake: After Klinger throws his ball, his arm stays extended outward. As the shot cuts, looking down the lane towards him, his arm is hanging straight down. Then, after the strike, he raises both arms up. A second later, his left arm is down by his side, his right doing a celebratory motion.
Other mistake: Looking at the pins when Margaret bowls at the end, the 5 pin slides backwards towards the camera, but not fast enough to bounce off anything and then fly in from off screen. Granted this was done in slow motion, but the physics don't seem to add up.