Photo scavenger hunt. Have a (trusted) friend prepare a list of things you have to photograph, such as a blue food, burnt out street light, etc. Make them seal it in an envelope so even you don't know what you're going to have to do until you both open it together. Makes you wander around even empty towns finding interesting things you never thought to look at before.
If not that, then I second Ed's picnic, and I'm also tossing in Miniature Golf, which is generally fun and gives time to talk (which you don't get with movies/tv).
-Adam