For each of my kids I made a poster of them growing up. The best one was the youngest kindergarten graduation pic next to his high school one. I put out their diploma and some awards and trophies and ribbons they've won. I also pull out the "sappy" homemade Mother's Day cards I've saved.
A bit of embarrasment on their part, but it's so much fun to reminisce over how they've grown up (and a few tears for Mom as her baby becomes an adult :( ).
We put on their cake- the college name- her she/he comes! It's a way to say they're still not ready to fly solo.
I also put out photo albums for people to look through.
We also do karaoke since I have some super wild sisters. And dance (after the fuddy duddies go home). It ends up being memorable for the kids. I make the friends stay over and do a big breakfast the next morning too.
I love having parties for my kids!
oh- food- I always make chocolate chip cookies and rice krispie treats (recipe on the side of the box) and have red licorice. For whatever reason, my kids think they are party foods.