The first go-kart-racing track was a circle because it was designed to teach children how centripetal force feels without rolling them down hills in tires. Learn circularly with today's Groupon to Competition Racing in Lawrenceburg, Indiana. This deal expires on November 18. Choose between the following options:

• For $16, you get two eight-minute open-race sessions for one person (up to a $30 value) with helmet rental (a $1 value; up to a $31 total value).
• For $31, you get four eight-minute open-race sessions for one person (up to a $60 value) with helmet rental (a $1 value; up to a $61 total value).

Competition Racing's freestyle indoor-racing track stretches 950 feet around 11 turns of high-speed motorway. Acceleration aficionados can suit up with helmets and duct-tape a miniature GPS system to the dashboard for eight minutes of adrenaline-attended action. Older racers rev engines in European-style karts that can zoom from fro to fro in excess of 35 mph, and kids accelerate up to 25 mph in youth karts. A protective row of retired stock-car tires runs along the edge of the track, buffering wide-turning karts and allowing enough space for three karts to drive next to each other, letting stooges or blind mice compete simultaneously. Drivers can track their position, laps completed, lap times, and best lap time on the facility's digital timing-system display. The time can be seen above the kart's steering wheel and on TV monitors during the race, motivating those voracious for velocity to attempt a spot on the wall of fame for fastest times.

Kart-bound bodies should call ahead for availability during scheduled hours to make sure that the track is not occupied by a private party or an army of clowns who have each demanded their own individual car and contracts with major companies to stitch business logos onto their clown pants.

Though Competition Racing sometimes features a discounted price online, this Groupon still offers the best deal available.