From Stunts Wiki
Stunts Challenge (often referred to as stuntschallenge) is an innovative online service set up by a group of Finnish racers fronted by wind. Stunts Challenge allows racers to publish their replays to high score tables with minimal fuss, be it just for fun or as part of an informal challenge. It is also a convenient way of sharing tracks, as adding a track to the database simply requires submitting a replay driven in the track. Additionally, videos are generated automatically for each submitted replay (such functionality, however, is not working for new replays as of February 2013).
Stunts Challenge replays should be driven with the standard BB 1.1 version. All sixteen cars used in ZakStunts season 2012 are recognized by the system.