Was looking at running / riding events in 2013 to do come across this thought it may be off interest to those with mountain bikes http://www.maxadventure.com.au/wombat100/
Starts 14th April 2013
Snippet from there website
The Wombat 100 is a cross country MTB marathon staged in the Wombat State Forest on the outskirts of Woodend, VIC. Regarded as one of Victoria’s premier XC marathon events, participants can expect a world class marathon course that includes over 50% flowing, groomed single track (including the famous Wombat track), fast fire trail, pine forest single track and 4WD trails. No tarmac, guaranteed!
I have done some 4wding in Wombat state forest never ridden there as I'm in the South Eastern Suburbs but will make the trip up for this as it would be a good place for a ride.