summer activities for 13yo

I have a 13yo boy and am beginning to think about the summer.  If you have/had a young teen, what activities did they do during the long break?  He has tried CIT type of things and will probably do them again, but not every week.  In the past, he's had some weeks of nothing planned, but again don't want that every week.  He is still interested in some camps for older kids (through Cal, The Crucible mainly), but it seems there are not many.  He's too young to get a job, isn't he?  I should also say that transportation (for some half-day/middle-of-the-day activities) would be an issue some of the days as both parents work.  I'd love to hear ideas.