You need to do a Google search, but there are games that are fun and I've never been to a party where everyone was required to play. If you don't like games then don't participate. Since you will be coming up with the games, then it makes sense that you will be directing the games and thus don't have to play.
Simple things to give away prizes for:
Put stickers under certain chairs in which the person sitting there gets a centerpiece off a table or a prize.
Freeze small plastic wedding bells in ice cubes put in the punch and give away a prize for those people.
Written games:
Put together a list of marriage words like honeymoon, wedding cake and so forth....scramble them and give everyone so much time to unscramble.
Give everyone so much time to create a list of as many famous couples as they can.
Have everyone write down a piece of wedding advice for a small little candy prize.
Longest married couple gets a prize. Newest couple gets a prize.
Get a list of questions together for couples to determine how much they know about eachother...the couple that comes up with the most correct answers wins. Examples: what color is his tooth brush, what is her favorite flower, favorite colors, favorite foods, date of first date, and so forth....
And again try a Google search and then hit some bookstores for shower game books.