A horse racing track with grandstand and stable.

The fence gates at the start can be opened from the outside in using a redstone line and repeaters from the grandstand.

The bottom of the track is made of coarse earth and in the middle there are two fountains with glowstone on the bottom.
The stable inside has room for 4 horses. The doors can also be opened with a switch.

There could still be a snack bar or betting booth behind the bleachers.