A few fun shots:
Tr/Urchin/Outpost/Masq - nobody sees it coming and they are too busying trying to make Merc work. Everything costs under $5.
Kc/Outpost/Masq - no engine potential (so people have a hard time shoehorning in a reliable Masq later) and gets done a lot quicker as you burn 5 cards a turn. For fun you can go Kc/Kc/Outpost/Masq/Discard (e.g. Militia) and win out in 3'er.
Cutpurse/Masq/Two villages/gainer. This is a highly amusing pin - you can not all deplete your opponent's deck, but also take it over. Play Masq (pass a copper, gain a card) -> Cutpurse (Opponent discards a copper) -> Masq (pass a copper, gain a card) -> Cutpurse. You need to play 10 terminals a hand to pin, but you can greatly accelerate your deck by swiping your opponent's villages/draw/etc. I'm a fan of Cp/Masq/Iw/Village/Farming Village. Tricky to setup, but I have never lost a game where I've tried this after getting even the most basic rhythm going (and I played variations every time for a while back on Isotropic).
Like above but even more screwball: B-crat/Masq/Two Villages/Gainer. Pass them estates, top deck them, and trash a silver. You can steal everything but green, and you empty the silver pile ... but they give you every useful thing in their deck.
For a speed run, I think your magic cards are Baker (in Bm deck if need be), Squire, Upgrade, and Scheme.
Open Masq/Upgrade with shelters. Buy Sqr, trash them (into Sch with Upgrade if you can) to get Goons. Upgrade Goons -> Kc.