You'll need pizza dough and pizza toppings. And a grill.
You can use your own pizza dough recipe. I'll post an instructable on pizza dough soon maybe.
Step 1: Cook the Crust
Take your dough and roll it out about the size of a dinner plate. Put on the grill for 1-3 min over direct medium heat, until it's crisp and brown, but not burnt. If it's getting burnt, take it off. Pull it onto a plate with a pair of tongs or a fork so the uncooked side is down. Or, if you have a wooden pizza peel (dusted with cornmeal), pull it onto that instead.
Step 2: Top It Off
- cheese (mozzarella or Parmesan)
Slide the pizza off the plate and back onto the grill over same heat and grill until cheese is melting and toppings look tasty and delicious and cooked, probably about 3-5 minutes more. Slide off grill onto plate.
If you want, make your own mozzarella to put on the pizza - see Homemade Simple Mozzarella on instructables.
Don't forget to turn off the grill. I usually forget.