There are a million ways to answer this question. As said before, just about any potato dish can be done on a grill, but if you are looking for something that helps to carry the "barbecue" theme then try one of my favorite potato "hobo packs." Peel and slice (about 1/2 inch thick) a number of sweet potatoes. Par boil them just until they not quite done, drain them and let them cool. One a large piece of aluminum foil place a couple pats of butter, then layer the sweet potatoes, caramelized onions, cooked & crumbled bacon, cheddar cheese, and salt and pepper (you can also add a little cayenne or chipotle for heat, or even sliced fresh chile peppers). Top with a few more pats of butter then wrap the whole thing up. I then wrap in another sheet of foil and grill over indirect heat for about 20-30 minutes (depending on heat of grill and how big you made the pack). Didn't give amounts as this is one of those recipes that can easily be made for 2 or 10 (though for more than 5-6 I would do at least 2 packs). It is also easily customizable: like bacon, add more, don't like onions add less, etc. Hope you like it!