(Witch Hunters, 3rd edition)
1 Inquisitor Lord w/ Familiar, Penitent, and Chiurgion
3 Priests w/ Eviscerators
2 max squads of Arco Flagellants
1 max Squad Sisters Repentia
2x Inquisitorial Stormtroopers (preferably w/ no special weapons or transports)
9 Penitent Engines in 4 squads
If you are not familiar with the WH codex, here's what happens: Your priests join the Repentia and the Stormtroopers. EVERYONE takes off in a ridiculous scramble across the board thanks to Holy Rage. For extra lulz, make sure to kick in the Arco Flagellants Stimpack Injectors turn one. All models can move up to 6+d6+6 if assaulting or 6+2d6 if you choose to run. This creates a mad scramble across the table, with units mixing into one another and causing havok as your lines start to get into each others way. And when they finally hit, the impact is ridiculously cheesy. Nearly everything has a chainfist equivalent (excepting the Arco Flagellants) which means that they can and will kill whatever they touch, but they are going to go last.
This is one of those epic, silly armies that will get you tons of entertaining games if your opponent is a total cheese eating type-A d-bag.