Originally Posted by kunilou
On some episodes of I Love Lucy, December Bride and some other old sitcoms, you can hear a relatively high-pitched, very loud "HA-HA-HA" on some laugh tracks. Supposedly (I can't remember the cite) that laugh is Desi Arnaz himself.
There's no doubt in my mind that was Desi laughing off stage. It's the exact same laugh he used in front of the camera.