We're doing an alternate-format tourney here in Seattle in a couple weeks (thanks, @Armada Jim ). As I understand, these rules are ripped off from Privateer's Steamroller format (and possibly also X-wing's Hangar Bay?), but I'm not directly familiar with either of those.
Rules are as normal, except:
Each player brings two lists, same faction but with different commanders.
At the start of the game, each player reveals his two lists, then each secretly picks one of his own lists to use, then both simultaneously reveal which they chose.
I'm pretty excited about it. I've also really enjoyed some other alternate-format events I've played in, particularly Monster Trucks.
So, what are some alternate-rules events that you've seen and thought worked well?