Grilled trout is delicious on a barbecue - never done it myself so can't offer a recipe but will try to dig one up (although I think it's just wrapping the fish in foil with marinade). My favourite barbecue recipe is marinading chunks of halloumi, red onion, peppers and mushrooms in olive oil, garlic, rosemary, oregano(etc. etc.) for as long as you can be bothered and then grilling them on skewers. Stole it from my mum who stole it from Delia so it is the height of uncool but really delicious. It's nice to have a chunky dish that isn't meaty too. Also important at barbies are quality salads: slightly warm couscous or better still bulgar wheat with leaves and good tomatoes.