I made a site for playing turn-based board games ( https://new.amecy.com/ ). Sign-up is free; I was eventually going to charge a small fee for extra functionality, but I haven't gotten enough users to make it worthwhile.

One of my main problems is that the site is not too useful unless you sign up. You can see what's going on on the site at https://new.amecy.com/main/observe , but it's clearly not as much fun as playing the games yourself.