If you are looking for pure (and extreme) adventure where few travellers have ever been, see the contributions by GLOBOmembers Jorge, Wojtek and some others:
Premium account Joined: Aug 04 Points: 35126 Posts: 171
Posted: 2008-01-30 22:32:00  
One of the most spectacular places that I've been to was the Grand Canyon. Also tracking the Inca Trail in Peru or trekking the Himalayas is incredible.
Queenstown for adrenaline sports alike bungy jumping or white water rafting or parachuting.
I quite like the idea of cycling Vietnam. But it really depends on what you like doing in general when travelling.