Okay, I just ran into the most insane brew on MTGO. Here's a rundown of this guy's play:
Turn 1: Mountain
Turn 2: Mountain, Ichor Wellspring
Turn 3: Mountain, Kuldotha Rebirth on Ichor Wellspring, Krenko's Command
Turn 4: Mountain, Krenko
Turn 5: Tap Krenko (12 total goblins), Battle Hymn, Battle Hymn (floating a bajillion mana), Reforge the Soul, Past In Flames, Ichor Wellspring, Kuldotha Rebirth, etc, etc, etc....
It was kind of nuts. Once he drops the "all my goblins have haste" creature, he ends up attacking with a crapton of goblins. Of course, I can't imagine the deck performs at all if you don't draw into a Battle Hymn, but it seems like a really fun deck to play when it all falls together.