I crack my knuckles before every match. Even when I know they won't crack.
When i do online Pokemon matches, I chew on my stylus. I've went through 2...
Sometimes when I Play fighting games, I quote along with my character. Examples: As Axel Low I always say "Resen Geki!" and as Sakura I usually say "E-ku-YO!" when shes does her 623K
I sometimes lean to the left or the right depending on what way I am getting ringed out from.
When I was 5, I used to stand up and stick out my tongue and move it in the most random fassion (I have a home video of me doing that lol, it makes me laugh)
I HAVE to have a jolly rancher and some juice to my right.