Anything you can have on a bbq, but done on the grill/george foreman thing if you can't be bothered to get the bbq out.
Fajitas/any kind of wraps, or kebabs, basically pittas with salad and fry up some chicken in butter or grill it. Add garlic to chicken if wished. Other fillings, falafels, tuna...
Baked potatoes done in the microwave
Chilli etc done in the slow cooker (or reheated from previously cooked frozen)
Salad, cold/sliced meats, pate etc, dips, carrot/celery/cucumber/bread sticks and crusty bread (everyone helps themself)
A big omelette/frittata with everything possible in, including potato.
If any of these are not filling enough or you don't feel like eating much, make a massive fruit salad and keep in the fridge for pudding. Have pudding about an hour after dinner. (ie eat little and often)