What kind of activity is by far the most popular in the world? I tell You: it is doing nothing. So why not develop a site for lazybones?
Yep, the target audience is really huge ;). But what to offer? Maybe some “things I have to do” exchange. Lazybone A would post activities, that he has to perform, but hates it. He would also post some activities that he offers to perform instead. Other lazybones would do the same. Hopefully, statistically there would be matches – activities hated by some lazybones would be really attractive for others.
For example: I hate cleaning my flat, but will slide on a snowboard or ride a bicycle, or slide on rollerskates instead. Does this sound interesting for anybody?