XMille is an implementation of the Mille Bornes racing card game. This implementation is played single player against a computer opponent. The card art is somewhat simple, but provides generally clear information on which card is which. Play is quite brisk, though is missing something without a human opponent.
This game predates the release of X11. In fact, it predates graphics at all, as there was originally a a terminal version called 'mille' by Ken Arnold from around 1982 that can be found in bsdgames nowadays. This graphical version uses some of the terminal version's code (uncredited!) and was written by Keith Packard for X10 in 1987, modified by Dave Lemke, then ported to X11 by Dana Chee. Steve M Robbins made some additional changes way later, in 2001.
The following is a video demonstration of the game, with an extension to a 1000 km finish line:
As a bonus, I also have a video of the terminal version on my YouTube channel, though that particular session got bogged down by an endless speed limit.
XMille is still packaged in Debian for now, though it's possible it might be removed for the credit issue hinted at above. If you are not on a Debian-derived distro, and your distro does not package it, you should be able to re-build the Debian source package.
More general information on old X games, including build tips can be found in the Old X Games article.
If the above video does not work for you, it is also available on my YouTube channel.