While the steak is on the grill, make your rub. Combine equal parts cocoa powder and chili powder. (I've seen a bottled version of the cocoa chili mixture in Stop and Shop, but I still make my own since I always have cocoa and chili powder on hand.
When the steak is done, dredge each piece in the rub, and you're good to go!
This one is pretty simple, but it's one of my favorites, so I wanted to share it.
I recently did some googling to find more steak rub ideas. While I was looking, I discovered a recipe that suggested using this rub for pork as well. That's something to try too!