Grand Theft Auto: San Andreas/Missions/Blood Bowl

The Blood Bowl mission can be found at the stadium in San Fierro. By going through the target zone you add time to your clock. If any car goes through the target zone it will move to a new location within the arena. The goal is to continue adding time to your clock until the current time remaining is above a certain amount. You will fail the mission if your car is destroyed or if you run out of time.

You also get more time for destroying other contenders, but this can be more time-consuming than beneficial. The cars seem to magically respawn, so you'll never be alone in the pit.