Challenging or gaming? Contesting or gaming? I think the whole radiohobby is sometimes a game. Although some people are taking it all (too) serious.
Remco PA3FYM and Rob PE1ITR are currently developing a highly experimental WSPR challenge. The challenge to receive as many WSPR stations as possible. Not easy, as transmitting WSPR is simple but you need receivers. Receiving a weak (-30dB) WSPR signal is much more difficult and so "receiving power" is more important then transmit power. The real challenge is to improve your receiver and antennasystem to even receive the weakest signals on WSPR. With the currently increasing environmental noise that could be a very hard thing.
Remco and Rob intend to make kind of a contesting game, with multipliers etc. Interesting not only for HAM but for SWL as well. I think it's a very nice idea and hope they will continue the development. Although I still would like to see a site were you can see the amount of DXCC you worked (or received), but that is personal of course.
See this highly experimental effort on: http://pe1itr.com/wspr_challenge/