Watch out, it can be mighty addictive! So much so that I'm now equal 11th out of 48,000 players and would do almost anything for an extra juicy point *cackles manically* Us players have even gone as far as writing a published book as part of the story.
For a quick lowdown on the cube itself check out:
http://www.perplexcity.com/thecube/index.qbuild
As I mentioned in another post, the cube has been buried for almost two years now and the pressure is on to find it - so much so that we've made more progress towards finding it within the last month than we have during the previous 20!