Any time before I pull a DL, I try and zone out as much as possible and properly fire myself up from within my own head, except keep my eyes open so as to not completely disassociate from my surroundings.
I stare off into the distance from standing (facing away from the bar) bend down and pull up my socks, take 3 steps forward, scratch my nose and spin around immediately, walk straight to the bar and heave.
It's the same every time. It's not too obvious, it just looks like I'm pulling up my socks and picking my nose, so no laughing.
Interesting thread topic!
Before a heavy squat or pull I'll ball my fist up and dig the nail of my index finger into the base of my thumb and squeeze as hard as I can for 2-3 seconds. Instantly takes my mind off of anything other than going to war on the next, usually last, set.
I light 100 candles and then cut my chest with a huge knife and then I do my cable curls.
does touching myself in the shower count?
I don't think I have any...really. I train with a guy who has a bunch. We use those "Iron Grip" weight plates at my gym.
When ever we load anything up, he has to make sure that all of the plates are lined up in a perfectly symetrical order. if we use multiple 45 lb plates, they must all be perfectly even with the flat parts lined up exactly. If he does Leg Press, He pulls the bottom of his pants down under his heel, and then steps on it so the pants do not move up while he is pushing. He has lot's of little habits like this.
TAKU
My friend does the Ronnie Coleman "LIGHTWEIGHT" before benching.
Golden Raptor - Before a heavy lift I always roll my shoulders forward a few and back once.
During a heavy lift I never break eye contact with my reflection and I always smile during it. It takes my mind off how much I'm actually lifting.
I couldn't smile during a max lift I'm afraid...to be honest, I've never tried.
TO THE GYM!
MightMakesRight - I stand in the squat rack and masturbate
hahahaha
I always go through my "erector set" check list, which is weight on heels, butt tucked, shoulder blades down chest out and top of head brushing the ceiling. I also find my self repeating "lunch pail and hard hat" on days I don't feel like lifting.
I'll admit it. I slap myself in the face before a PR set. My high school football coach did it to me once and I got so mad that I lifted 20+ lbs on a PR squat and ever since then I do trying to psych myself up.
When doing a heavy BP I lay back, set my hands, stare at the center of the bar, then pull my upper body up toward the bar 3 times exhaling, roll my head around to get "centered", pause then pull up toward the bar a single time. I then set my shoulders and lift. It's like I'm seeing the lift in reverse.
I hadn't lifted consistently in a long time but started back a few months ago working out with my sons.
I guess I was doing it before every set. Then my son asked me what the hell I was doing. Now I cut down to doing it only on heavy sets.
- As soon as I put on my mp3 player or put on my cup I have to take a shit. Every time. Without fail. It's like my body knows "it's go time" and empties the storehouse.
- I have a power phrase before every big lift or sparring etc. Mentally puts me where I need to be.
Before leaving to go to the gym I masturbate almost to completion and then stop.
I'll do the "Axe Murderer" hand clasp wrist roll before anything that requires gripping a bar.
Not really a ritual, but when i need to lift anything really heavy i'll start growling and grimacing to myself while i do it, and then spend the next few minutes avoiding eye contact with the chubby lady staring at me from the treadmill section.
Before my kettlebelll routine I kick my
Cat out of the way 
I used to stomp into the ground hard once with each foot before a heavy lift of the floor
With a heavy squat I grip the bar before I go underneath it and roll my wrists a few times, then duck under and get under the bar. Only something small but I noticed I did it a few weeks ago.
Only when maxing out or doing something that requires maximum effort or intensity.
On Max effort lifts (Squat, Dead, Clean or Bench) I always slap my quads, then ass, then abs/obliques hard to remind myself to get tight. Occasionally I slap myself in the face if I am not having a good day. If I am attempting a PR I usually get some hatebreed or as i lay dying pumping on the ipod, mean mug myself in the mirror and tell myself I am weak and will miss this lift.
LiftStrong - Only when maxing out or doing something that requires maximum effort or intensity.
On Max effort lifts (Squat, Dead, Clean or Bench) I always slap my quads, then ass, then abs/obliques hard to remind myself to get tight. Occasionally I slap myself in the face if I am not having a good day. If I am attempting a PR I usually get some hatebreed or as i lay dying pumping on the ipod, mean mug myself in the mirror and tell myself I am weak and will miss this lift.
This minus the mirror bit (no mirror in my garage) and different music. I always turn the music up just a bit louder before a max effort set.