pump track - stone berms
Better Homes & Pump Tracks by hukee, via Flickr
A track for remote control cars! - but would be great for kids to ride their bikes on with a bit of tweaking.
Backyard Pump Track
Aston Hill pump track
Cycle Trail Construction Guides: Pump Track
Pumptrack Luxemburg Pete Stutz 22
Pump track - need some design help - any gurus out there?
Garden with Pump Track eclectic landscape