Most people will find a 25th Anniversary party to be a time for playing 25th Anniversary party games and printable activities while interacting with friends. Various types of games are ideal for a 25th Anniversary party; however the key to this party and others is planning games that compliment the party itself and add to the event. Therefore playing games such as Never Have I Ever and Have You Ever will add to the party.
One thing that makes a search like this more difficult is that many sites are either directories or attempting to sell a calendar program. The latter usually have something free to give away, but if they want you to buy a program the one they are giving away is pretty generic. Don't waste time trying to make the free one work if it isn't perfect on the surface. There are other choices that are completely free. You may have to try several options, but if you are patient and persistent you can find a truly free and printable calendar.