The Grammys bring all of recorded popular music together under one roof. It's the only time you can see Snoop Dogg and Billy Joel at the same party (because Billy's a Piru for life). 

After several years of awkwardly sitting rap's biggest stars next to pop's schmaltziest, some enterprising show producer decided to bring that contrast to the main stage, throwing rap artists and pop artists together to see what sticks. 

Sometimes it works, oftentimes it doesn't. And that's why, leading up to the 57th Annual Grammy Awards on February 8, we've decided to take a look back at some of the strangest pop and rap combos the Academy has ever cooked up.