Do you know if a good animal/pest repellent?

It's almost garden time and I'm planning on growing some lettuce this year. However, I'm worried that my local bunnies will think I'm offerring a free buffet. They haven't done anything the last couple years when I've grown tomatoes and peas, but I don't think those are bunnies' favorites. I want to know if someone can recommend me a product that is natural and will just deter the bunnies (and any other hungry critters) from eating all my vegetables.