vegetarians dont need a special entree, its a common misconception, just make your sides without chicken fat, beef bullion, geletin(in desserts), rennet(in the cheese) or eggs, and have a veggie tray and salad. vegetarians make a meal out of the same thing meat eaters do, just no meat and more of the sides and salads. Your veg friends will be delighted that you took the time out to omit these items, when they probably would not expect you too.
Ive been vegetarian for almost 20 years, and i know of many. We dont expect a special entree made for us, but if a hostess allows me to look through her recipes, or assures me that there is no beef or chicken base or bacon grease in the sides than i am eternally grateful.