Play games like scrabble, cards, video games and the like. Put on some music and dance (the more experienced one can teach the other). You can teach yourselves the steps to specific dances and practice over and over again. Go bowling it's lots of fun. Play baseball in the park, go on the swings, you're never to old for that but there is lots to do in the park. Take a long walk and bring sandwiches for a picnic.

You will get lots of good ideas here from other people too.