I'm having a play with a new project which lets people play text adventures which are embedded in real world locations, and am after some beta testers to have a play whilst I develop new features. At the moment, its really rudimentary (you can create stories and rooms, and browse them in a basic player - everything is web based, and the interface is pretty clunky). But I plan to improve it incrementally over the coming months.
If you'd like to join in, the site is hosted at Xyxxy
If you log in and register, there's a 'learn' link at the top with tutorials - and I'll keep people updated as I roll out new features.
I've been writing everything on my iPad, so the formatting only really works on a tablet (and at the moment, its not the most beautiful of things - but it'll get there).
All the best,