Grimgrin was my first EDH general and still holds a special place in my heart. This deck does run the Rooftop Storm-Gravecrawler thing, but creatures that allow me to deal infinite damage to my opponents with Grimgrin (like Diregraf Captain) have been intentionally omitted. The deck is, of course, centered around feeding Grimgrin so he can do what he does best: smacking your opponents for massive amounts of damage and blowing up creatures while doing it.
-The core of the deck is Rooftop Storm with Gravecrawler which provide Grimgrin with an infinite source of sacrifices to make him huge.
-Harvestor of Souls draws tons of cards because things die all the time when Grimgrin is out.
-Both Grave Pact and Butcher of Malakir are effectively one-sided boardwipes with Grimgrin. People tend to scramble to remove them quickly but once I'm in a state to keep fueling Grimgrin it's hard for them to recover quickly.
-I put Corrupted Conscience under Grimgrin support because giving Grimgrin infect makes him even more lethal quickly. It can also be an alternate win-con if someone decides to drop an early Eldrazi titan or something.
-Vampire Nighthawk is, in my opinion, a very underrated EDH card. Who wants to waste a giant, awesome creature against a 2/3 with deathtouch? Certainly not your opponents. It can buy you a couple of precious turns while you gear up to dish out the hurt!