My friend had a BBQ a while ago, and as a veggie, I helped make some stuff for the othe rveggies there, an dit was actually really good. I'm craving these right now: Just skewer some red onion bits, with chunky bell peppers and mushrooms. Coat in oliv eoil, and place on the grill. It's damn good!
try portabella mushrooms, zucchini, tofu slathered in bbq sauce and new potatoes with olive oil and herbs on the barbecue. they're all excellent.
They taste great on their own but I also recommend whipping up a sweet satay sauce made from peanut butter to dip the veggies in. Another winner for us at a BBQ is slices of BBQed Cypriot Haloumi cheese...mmmm I'm hungry now