as a genre mexican lends it's self well to vegetarian. Replace the meat with beans and there you have it. (burritos, taco salads, veggie enchiladas)
While the weather is cold, there are also many soups that work well as vegetarian.
(look up varieties for squash soup, African peanut soup)
for sanwhiches look at lavash from t.j.'s or a local persian market and fill with feta, hummus, olive, tomato, lettuce, onion (its flat bread so roll it like a wrap)
asian- stir fries are great
Get a panini maker and fill them with roasted bell pepper, mushrooms, cheese, basil.............
Pizza. but get creative. you can buy pre made bread dough, and fire it up on the bbq
not the mention the endless salads you can create
best of luck.
(I am not strickt vegetarian now, but way back when, my roommates used to comment on the variety and interestingly appetizing foods i made (I was a strict vegetarian then), but would complain at the thought of going veggie and wondered what the hell they would eat. It may take an adjustment, but variety won't be a problem)