The only time I ever really had a ritual was when I used to race.
I would always get to the race location 2-3 hours before the starting time
I would listen to my ipod (usually heavy metal) and sit off by myself, drinking water and trying to clear my mind
At exactly an hour and 10 minutes before the start, I would go for my warm-up (2-3 miles)
Come back to stretch, do my drills
At 20 minutes before the start of the race, I would put on my racing spikes
Do a series of long strides at the starting line
5 minutes before the race, my team and I would go out 150 meters or so for the team huddle
2 minutes to go, I'd take off my warm-up jacket/pants, check spike laces multiple times.
Oh yeah - and the entire hour before your race your nerves make you feel like you want to go curl up someplace and die.