Standard Druid Roar, with a GvG mech twist.
Currently being played at Rank2: http://www.twitch.tv/reynad27
EDIT -- ranked from 2->top50 Legend!
Similar in nature to DTwo's List [http://www.hearthpwn.com/decks/141382-dtwos-gvg-fast-druid], but less early ramp, more early mech. You can decide what you like best. :]
This is an aggresive deck! You don't have wrath to fall back on. Mulligan hard for Mechwarper, Annoy-o-Tron, and other 4 cost or less cards. You will draw into the combo! Don't ever keep late game cards in your starting hand, they will be dead weight!