The attraction files for the Lego Rocket Racers Attraction (the 2009 ver, which runs properly on NT based OSes) were leaked a few days ago and with how well received the Daytona 2017 leak was here and how quickly you guys broke it open, I thought I'd share it's leaking here.
Currently it requires at least 3 PCs to actually start a race, one for the Attendant's control panel and master server, one for the character creator (1 per cart), and one for each cart, but they all use the same executable which is launched into different modes for each system. I'll bet that can be brought down to 1 machine and 1 batch file with ease. I'll note it's not super exciting, but it does use assets that were never seen in other LEGO Racers games and is an actual racing game.
The leak itself can be obtained from the usual sources (it's mislabeled as "Lego Racers Betas"), just make sure you grab the complete version and not the partial that was posted first.
Player Training Video:
Blog post describing the system in action with pictures.
http://www.cllw.co.uk/attractions/beginning/rocketracers.php