N.K.
Pay attention to the time of day. If you don't want to have to really feed everyone, make it an afternoon tea party, or something to that effect. You could offer a variety of teas, and then cookies, scones and muffins. Offering it in the afternoon also gives you all morning to prepare and set up, and then have a whole evening to wind down.
This isn't really a game, but a nice activity is to have everyone attending write one piece of advice to keep the marriage strong, and then to have the bride read them outloud (assuming there aren't a ton of people there)
I am a pastry chef, working from home, so if you would need any pastries, or cakes, for either event, feel free to contact me for menu, pricing, and ideas!
Good Luck!