Stunt Rally (2010)

Stunt Rally is an open source racing game with a track editor. It focuses on closed rally tracks with possible stunt elements (jumps, loops, pipes).

http://code.google.com/p/vdrift-ogre/

DOWNLOAD — (Linux/Windows) http://sourceforge.net/projects/stuntrally/files/

ManiaDrive (2006)

ManiaDrive is a free clone of Trackmania, the great game from Nadéo studio, and is an arcade car game on acrobatic tracks, with a quick and nervous gameplay (tracks almost never exceed one minute), and features a network mode, as the original.

http://maniadrive.raydium.org/

DOWNLOAD — (Linux/Windows) http://maniadrive.raydium.org/index.php?downloads=yes

SuperTuxKart (2004)

SuperTuxKart is a Free 3D kart racing game, with many tracks, characters and items for you to try. Have fun!

http://supertuxkart.sourceforge.net/ 

DOWNLOAD — (Linux/Mac/Windows) https://supertuxkart.itch.io/supertuxkart 
entry suggested by @joakimikel