More to explore:
Park Tool Wheel Tension Balance Web App
Park Tools Wheel Truing Stand
Top 10 trail building tools - MTB News | MTB Trail Building | Seeking Out The Best Trails In The World | Mountain Bike Magazine !!Yeah!! Trail working time! The best trail is always your local :)
Pump track ideas.
Lefty fat bike
World's Biggest (only?) underground bike park set to open Jan 2015. It's in an old mine in Louisville, Kentucky