For your Anniversary party theme, here is a game idea that can be altered to fit the Anniversary party theme.
Check out Anniversary
Party Games for more free party games. An anniversary party is fun time to renew your vows in front of close friends.
SPOOKY MOVIE NIGHT: Rather than the usual fancy dress hold a Halloween or sarcy film evening. Rent a DVD a 'spooky/halloween' film (suitable for the age group) and have popcorn, hot dogs and drinks. You could finish the evening off with a ghost story.