Years ago during the FOX pregame, I would shout "ON TAP" in unison with the FOX narrator guy person thing and felt that was a good 'omen' for the Packers. They stopped doing the On Tap thing and so did I.
The last 'ritual' or superstitious thing I did was during the end of the 2010 season I started doing the Insanity workout. If you've done them, you know you need extra motivation from time to time. Well, month two coincided with the playoffs and when I wanted to give up, I would tell myself "If I 'demand' the Packers give it that extra, I better do the same thing" ... or something on those lines. Basically, told myself I couldn't push others to push it if I was going to slack. I ripped through those final four weeks like a damn mad man.
As a kid I would also have my Packers blanket that my grandma gave me when I was about 11 years old during game day's. There was one game that sold me on it being legit. We've all been here before where you go "Why the hell are they losing? They are better than them!" and then I remember I didn't have my blanket. I grabbed the blanket and like clockwork, the Packers stormed back and won.
I also used to wear a Packers jersey. White if away, Green if home, but not really any superstition to it that I can remember.
During game days now I have too many things going on to worry about rituals or the like.