Adventure racing vs Ironman

Oh no, my head has been turned to adventure racing by a colleague...... I know I'm already signed up for a 70.3 and I'm looking to do a full ironman in August but these do look interesting

http://www.arwc2007.com/
http://www.dynamicadventureracing.co.uk/
http://www.ecochallenge.us/
http://www.ecoprimalquest.com/

Crumbs up early tomorrow for 6 hour drive north to Scotland, trainers and tea bags are packed?!