My husband loves to grill in the summertime, and this worked out great--I know it's too simple for the gourmets in the crowd...

but it worked for me, so I thought I'd post it.
Easy Grilled Fish
Frozen fish (not breaded), such as tilapia, which is what I used, whiting, haddock, cod, or other already fileted fish, ready to cook.
Fresh or bottled lime juice or lemon juice (I used lime in the squeezy green plastic lime, 'cause it's what I had)
Spreadable margarine or butter
Aluminum Foil
Let the fish filets thaw. Put each filet on a single piece of aluminum foil that's big enough to wrap around the fish to keep the juices in. The Reynolds wrap individual sheets were the perfect size for me.
Squeeze or spoon 10 to 15 drops of lemon or lime juice directly onto the fish. Spread about a half tablespoon of margarine or butter onto the foil near the fish filet. Wrap up the filet in the foil to seal in the juice.
Throw the foil packet on the grill, cook 'til done (the time varies by grill, but somewhere in the 8 to 14 minute range). When the fish is almost done, unwrap the foil and put fish back on the grill for 30 seconds or so on each side to get some of the smoke flavor.
Serve with side dish/veggie of your choice.
Note: When you want to start experimenting, you can marinate the fish in almost anything that appeals to you, starting one to two hours before cooking. Marinades I've used in the past include Italian dressing, red or white wine, red wine-vinaigrette (don't leave in this one long, it can make the fish tough), Russian dressing (my husband liked this one), milk, salsa of any kind for a Mexican spicy flavor, etc. You can also use almost any rub, such as Cajun, Caribbean jerk, etc. We try something different almost every time we grill...