GOAL! . . . GOAL! . . . GOAL! . . . Bring a drum, and Old Glory. Hey and if your lucky you might get into a right proper row (gang fight) what-what.
Maybe not the best spectator sport but to each his own. On the other hand it's a great participant sport. Arrange for a tournament the day of the party, that way the groom can say he went out swinging. You might want to rent carts. Wouldn't want to waste energy that might be better spent fondling naked strippers.
Rent a house boat and fill it with liquor and plastic women/sheep and good things will happen. Arrange for one of your friends to bring a smaller boat to use as a taxi, so you don't have to keep going back and forth to the marina to pick guys up. That can take awhile in a house boat. Most house boats have ample room for cold drinks and a barbeque grill, so bring beer and beef. Be sure to tell the guys that it will be BYOB&B;. Large amounts of beer will impress the guys, large amounts of USDA Choice will impress as well. Chances are you can even get a stripper to show up on your boat. Check with the marina, they may have a binder of business cards you can look through. Strippers know where to find you.
Or if you live near a large body of water you may want to charter a party boat. Appropriately named and able to handle your whole crew. Be prepared for the eventual and bring Dramamine. Remember puke in designated receptacles (i.e. the ocean).
You name it, as long as you add beer, vulgar language, stories of large breasts, and your buddies-you can't go wrong.