Steven Luo didn't have access to World of Warcraft when it came out nearly nine years ago, so he decided to make his own game using Warcraft III's editor tools. This year he ported the mod idea fully into StarCraft II, as WoW RTS: Alliance and Horde, or WAH for short. He spent six months working on it part time, then decided to quit his job to spend another two months finishing it.
The mod contains three maps right now, and you can find them on the StarCraft II Arcade by searching for "WAH." I haven't had a chance to play this yet, but I am looking forward to diving into it as soon as I can. I loved Warcraft III a lot, and I am bitter that we haven't had Warcraft IV yet. Hopefully this can satisfy me for awhile.