A woman playing a piano with baseballs (Jenny Q Chai playing Annie Golsfield's "Brooklyn - Oct. 5. 1941")
A monkey on a goat on a cup on a tight rope.
"Stairway to Heaven" backwards (original recording played backwards)
Foo Fighters playing "Stairway to Heaven" backwards live on the Late Late Show with Craig Kilbourn
This came up by searching "monkey playing backwards with baseballs"