Mox-Nix, QT, and Side-Show Bob

So, after a much fruitless discussion with a friend, I'm offering these three up for discussion:

"Mox Nix" (which I've also seen as Mocks Nicks, but that seems wrong to me...) There is some mention of a WWII reference and the German "Machts nichts." If anyone can provide a literal definition in addition to the background, that'd be great. Particularly, if someone says "I'm Mox Nix on disco music" -- does that mean he/she is ho-hum on it, or that he/she actively dislikes it?

"On the QT" I understand on the DL (Down Low), but QT? All I can think is QuieT... And are DL and QT recent phrases or wartime acronyms?

Finally, "Side-Show Bob." If you've ever been to Dim Sum, you often hear people ordering "Side-Show Bob." I know that this is the Americanized version of the name for BBQ pork dumplings, but I'm wondering what the actual name is in Chinese (in roman script please!).

Thanks all.