The [couchsurfing.com] group’s philosophy is also its method, which might be summed up this way: I will offer you my couch free, along with the company of my friends and a tour of my favorite spots in my city. In return, you will give of yourself, and not just slink into my home at 3 a.m. after you’ve done your own tour of my city. In this way, we will be friends, if only for a day or two.