Black Sabbath did "Smoke on the Water" when Ian Gillan was with them. For those who don't know, Bev Bevan (ELO) was the drummer for that tour. He was Geezer's neighbor. I interviewed Gillan on that tour, and he joked that they had talked about doing "Telephone Line" for an encore.
Uwe's EDIT: They actually did rehearse Evil Woman (the ELO, not the Sabbath track from the 1st album), but then didn't have the guts to play it. "Born again" is an underrated classic.
There's no video out there, but Hunter/Ronson did one of the coolest versions of "Day Tripper" ever. It was a little slower, and very slinky.