Downhill Challenge happened in 1988.
Downhill Challenge was created in 1988.
Downhill Domination happened in 2003.
Downhill Slalom happened in 2006.
Tony Hawk's Downhill Jam happened in 2006.
No Fear Downhill Mountain Biking happened in 1999.
If mud slides downhill, then yes, gravity makes the sliding downhill happen.
Supercar Challenge happened in 2009.
Rugby Challenge happened in 360.
Lotus Challenge happened in 2001.
GP Challenge happened in 2002.
Challenge of Barletta happened in 1503.
AFL Challenge happened in 2009.