I'm not sure what to call them - facetious equations? humorous formulae?

But there's Adam Savage's famous "Science + Beer = Good" (which I think would make an awesome and popular t-shirt, and I'm not even a beer drinker)*

But here's another one: Stuff + Cats = Awesome (the link is to my current favorite image; the main site is here)

And, yeah, yeah, I suppose some of that stuff was kinda mean to the cats. But somewhere my mom has a photograph of me sitting next to Sam, the cat we had when I was growing up, and Sam has one of those cardboard "L'Eggs" pantyhose things on his head. I think it's a universal human desire to put stuff on cats. ("It is a truth universally acknowledged, that a person in posession of a cat must be in want of putting stuff on it"?)

(*The reference is to the Mythbusters episode where they tested methods for making beer cold fast. The general conclusion was that if you didn't mind paying for the cost of the recharge, using a CO2 fire extinguisher on the six pack worked best. Probably not recommended for beer in glass bottles).