While I'm on the roll of recommending websites with something fun or inspiring to do, let me mention Post Crossing. It's a website that organizes the swapping of postcards with people all over the world. I've been a member for about a year now and have really enjoyed receiving postcards from somewhere new every so often.
My initial intention, when hearing about Post Crossing, was to get my kids involved. But like any kid of their generation, they don't really care for things that involve pieces of paper and stamps. Why send a postcard when you can send an email? Perhaps it's the reminiscent part of the whole process that's enjoyable to those of us older than twenty. I'll admit that I adore all things technical but I also enjoy getting mail and enjoy sending it, even better if it's something pretty like a postcard.
So, while I would sell the idea by saying it's a great thing that you can do with your kids this summer, in reality it will be you that enjoys this.
Here are a couple of my favorite cards: