Some time ago, Microsoft Research (MSR) made Pex (a white-box testing tool) universally available in the form of a web challenge, called Pex for fun. Pex for fun followed the great example Project Euler, striving to build a challenge-oriented community while allowing “players” to familiarize themselves with the basics of Pex.
Now, MSR and more specifically the Research in Software Engineering Team (RiSE) of MSR made some of the known (and some of the lesser known ones) applications and libraries available in the same convenient, easily accessible Pex style, i.e. via a web interface.
Just head over to RiSE4fun and try your favorites: pex, rex, spec# or z3. The site has a twitter-like real-time feed called live and more importantly supports a REST API. Using this API you may, much like Pex which already exists on Windows Phone 7, build your WP7 variant of a RiSE app or you may use a RiSE tool like the Stanford Parser - online.
With that, enjoy and put the fun in exploring RiSE4fun.