My favorite variety appearance is actually the show they ended up starring in called Explorers of the Human Body. It is both funny and somewhat educational. Each episode explored different parts of the human body and answered questions people had by doing experiments with their bodies. This is also the first time ALL the members of Super Junior appear on a variety show, though I think there is one missing or has to leave every episode. Due to the bad car accident, Kyuhyun isn't in the first few.
By far one of my favorite episodes is where Super Junior tried out laughing gas. This is so funny and it never fails to make me laugh.
There is also part of an episode where the members pull a hidden camera on EunHyuk and Ryeowook to make them cry. There members are to collect their tears.
I felt bad for EunHyuk though.
There are other episodes that are fun to watch also, so I hope you check them out.