Downhill Challenge happened in 1988.
Downhill Challenge was created in 1988.
Downhill Slalom happened in 2006.
Downhill Domination happened in 2003.
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.
Winter Challenge happened in 1991.
AFL Challenge happened in 2009.
NFL Challenge happened in 1985.
Brain Challenge happened in 2007.
Aztec Challenge happened in 1982.
Quad Challenge happened in 1991.