get a bunch of pallets they're the foundation for most trials courses/obstacles. also the blue pallets are slightly larger and much stronger than regular ones.
Here's some pics and video's of 'HoW's trials park' (http://gallery.unicyclist.com/album162) . John just built an awesome teeter-totter which we'll have pics and videos of soon.
Do some searching and if your lucky you'll find two threads that were here quite a few months ago. Both were really cool trials courses the people had setup, if you can find them they would be really helpfull.
Klaas Bil - Newsgroup Addict -- Today (3 January) is the first day this year that is neither the first day this year nor the first day this year that is not the first day this year.