I'm always a fan a veggie pizza. You just get a reduced fat crescent roll package, spread it in a pan and bake until golden. (make sure to pinch all of the corners and sides together) Let it cool, and spread on any low-fat soft cheese or flavored cream cheese. I like low-fat garlic herb cheese that comes in a tub! Then just cover with chopped up veggies of your choice, I use carrots, peppers, broccoli and reduced fat shredded cheddar cheese. Cut in to squares and serve. Your guests will love this simple, light, and yummy treat!
For a sweet touch, I love to do dark chocolate fondue. Kind of naughty, but when you throw in a bunch of fruit to dip, the amount of chocolate you eat is very minimal.
Hope this helps and have a great party!