I can't believe no one has mentioned....
Remove the stem and scoop out the gills of a portabello with a spoon. Brush with any sort of spiced oil you have and grill, cap side down. Brush the gill side while the cap is cooking and turrn over the mushroom(s) after about 5-7 minutes. I haven't figured out what to do with the stems because I keep eating them after I pull them off the mushrooms.
The trick here is to skewer them together, like a little raft but before you do that, soak your skewers (if they're wood) for about 30+ minutes. After you have your "rafts", brush with your spice oil and grill until sweetly tender, about 2-3 minutes while brushing the other side. Turn and grill for another 2-3 minutes.
Slice these somewhat thick and skewer them (so the rings don't come apart). Grill until marks form and the onion goes somewhat soft - maybe about 3+ minutes (I rarely time these things). Turn and repeat. Remove the skewers before serving.
Peel back the husks, but don't remove them. Desilk the cobs and brush liberally with either a spiced oil or a compound butter made with Earth Balance and whatever spices you like. Pull the husks back to place and tie them with a bit of husk string (usually one or two husk leaves fall off in the desilking which are great to tear into strips for ties). Cook for 5 minutes, roll them a quarter turn, cook for another 5 and do this until all 4 sides are cooked - about 20 minutes total.
Really sugary fruit like peaches, pineapple, etc can be grilled quite well (hint: if you can bake it, chances are it will grill well, too). Be sure to only grill for a few minutes, and don't let them go to mush. Serve with a scoop of Soy Delicious on top or a drizzle of maple syrup.
Someone once said that if you can roast it, bake it, or fry it, chances are it will be great grilled.