they are quite nice stuffed with spinach and ricotta. Just fry onion in oil, add spinach, season well ,add a bit of nutmeg then mix with ricotta cheese...bake in oven!
This might be too pedestrian, but I always enjoy a tuna tomato (especially on a hot day)...mix together some drained tuna fish with mayonnaise, relish, chopped onion and chopped celery. Stuff it inside the tomato.