When I covered actor, supporting actress and actress, I combined all the competitors into one fictional composite character... but with this category, what's the point? The only thing you must know (if you don't already) is that this guy has serious psychological issues. Whether he's a mathematician, a pedophile, a super villain, a politician or an acclaimed actor, he's just plain nuts! Mental disturbances = your surest way into the Oscar race (if you have a penis. For actors with vaginas, the rules are a bit different)
Over at the Supporting Actor Page there's detailed silly theorizing as to how each contestant got nominated as well as a poll that pleads for your take on this race (preference wise. After all, we all know what to predict). Who do you think gave the best performance? Robert Downey Jr, Philip Seymour Hoffman, Michael Shannon, Josh Brolin or the late and greatly missed Heath Ledger? Or here's a better question for the comments... who comes in second place for you?
Personally I was annoyed at first with PSH taking up space yet again but I think it's a very solid lineup when all is said and done -- any line up with three genuinely inspired performances (and two of them off preferred genres at that) is worthwhile. I wasn't completely sold on Michael Shannon's performance either actually (in Revolutionary Road) but I've loved him since he went completely starkers for the great play Bug here in NYC so I'm glad he's now winning mainstream attention.