sex on the beach is a must------cocktail that is.
I was on holiday a while back and they had a competition about inventing your own cocktail, and who ever won got it named after them...some silly made up name or what ever they wanted to call it.
So you submitted your ideas and then 5 were picked to be in the final, then people would buy the drink to see which they liked and then voted. I'm not saying each person would but all 5 cocktails but they might try a few. Either way your'll make profit. You dont have to make every suggestion that is given just pick out 5 that you like the sound of, and just make them when people order them.
Something "free" is always going to bring in a crowd. Could put on a small selection of free food like pringles, sausage rolls, sandwiches ect. Then the bbq that people would pay for, just dont look to make a huge amount on the food. The better deal it seems the more people will purchase.
Organise some silly games....i cant think of it's name ( duh ) you have to go under the pole, muscial chairs ( i know it's a kids game, but still fun when your drunk ) do a few spots prizes of a free drink/cocktail for the best dresses, the worst dressed, have a raffle to win something ( maybe you do food in your pub could be luch/dinner for 2 )