The Muppet FAQ is full of amazing Hensonania and Muppet lore:
Why are Muppets left handed?
You may have noticed that Muppets, particularly Muppet musicians, tend to do everything with their left arms. This is because most Muppet performers are right handed and use their primary hand to control the head and face of the Muppet. (Louise Gold is one of the few left-handed performer, and her Muppets are right handed.) This leaves them their left hand to control the Muppet's arms. Muppets like the Swedish Chef, which are controlled by two performers, are of course an exception….
Answers to some particularly frequent ID requests:
* The guy who throws fish: Lew Zealand
* The guy who blows things up: Crazy Harry
* The scary-looking blue monster: Uncle Deadly
* The piano-playing dog: Rowlf
* The guy who hits his head on the piano on SS: Don Music
* The yip-yip aliens: Bob and Joe MartianWhat's the best ever Muppet sketch?
Mahna Mahna, with Mahna Mahna and the two Snowths. Even now, you sing "doo doo do doo doo" under your breath every time someone says "phenomena," don't you? You know you do.
(via Memepool)