Hugely superstitious here. I make my wife wear the same OU T shirt every time they play a game. Also have to have my teddy bear watch games with me. I have had him since I was like 6 months old, he even has his own jersey my mother made. I will change shirts or hats if things aren't going well during a game.
Once, my wife re-arranged our living room furniture a couple days before Bedlam Game and i had a really bad feeling about the game. OSU went into the half leading so I rearranged the furniture back the way it was, first carry of the second half Peterson ripped off an 80 yard TD, OU won.
We went to Europe last summer during world cup. First game Italy played I wore my blue jersey, they won, game 2 I wore the white one and they drew the US, I have yet to wear the white one on game day and never will again.
Also while we were there, some quasi homeless guy came up to us in Milan and "gave" my wife a bracelet (one of those handmade string ones teenage girls make) for a small "donation". He claimed it was lucky (whatever), I don't want one but for fear of bringing bad kharma (it was the day of Italy/Australia) I give him his "donation" and take the bracelet. Obviously they won that day so now I was all neurotic about the stupid thing, that it would fall off before the next game or the next game or the final. Damn thing is still on my wrist literally 9.5 months later.