Enduro is another Activision classic, and the best racing game on the Atari. Grand Prix is also pretty fun, and of course there is always Pole Position. Enduro is more like Outrun, you drive across varied scenes at high speed.
Game features, ice, fog, day and night effects. Easy to pick-up and play, very impossible to master. A must have for any collector. Included in the Activision Antology for GBA and PS2. I own both versions, as they are excellent and have a nice virtual interface.
The main thing I like about Enduro is how long the races last, you'll be driving for minutes, instead of the seconds most other racing games of this era provided.