One way to experience several different types of riding conditions while staying on the same machine is to ride a Dual-Sport motorcycle. Central PA is home to one of the nation's largest offroad motorcycle rides: The Annual Durty Dabber Great Adventure Dual Sport.
http://www.durtydabbers.com/trials/wp-content/uploads/2011/04/Durty-Dabbers-14-Flyer-2011.pdf

Formed in 1979 with ten members, the Durty Dabbers today has over 100 actively participating members who organize, coordinate, assist, and ride in various dual sport and observed trials events.
 

The Durty Dabbers held their First National Dual Sport in 1990 with approximately 100 riders participating. Now in it's 21st year, the annual Dual Sport ride attracts close to 600 riders from all over the country. The event is every year the weekend after Memorial Day (usually the first weekend in June) and will be held this year June 2 &3 2012 in Lock Haven PA.

http://www.durtydabbers.com/?page_id=8

http://www.youtube.com/watch?v=4xjioH5PPiE