The Main Monkey Business is an instrumental from Rush's 2007 album Snakes & Arrows. It clocks in at 6 minutes and 1 second, making it Rush's second longest instrumental, the longest being "La Villa Strangiato". Drummer Neil Peart remarked that it took him three days to learn the song.

The title of the song comes from a phrase Lee's mother used to describe someone up to no good:

...Long story short is, uh, this person was up to hijinx and my mother was telling me “Well I think there was some monkey business involved”, and I said, "What do you mean, monkey business? What kind of monkey business? And she said, “The MAIN monkey business”. So I love that phrase and every time I think of her saying “The MAIN monkey business” it makes me laugh.

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