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2.
Cheating on ones significant other
Dude 1: Can you believe Jesse James is going off-menu for Marilyn Manson?

Dude 2: Dude, apparently she lets him park his hot rod in her monster garage like 5 times more per week than Sandra Bullock.
by don't ask jeeves September 06, 2011
 
1.
choosing an option that wasn't presented, whether that be on an actual menu or in other phases of life
I'm tired of this same old food. I'm going off-menu with this one. I want a Big Mac, but with only BBQ sauce, Onions, Lettuce and cheese.

Known versions of going off-menu include, but are not limited to: the McChurger & the McOctogon
by Insidivs February 02, 2010