To unlock Dem Bonez, you must break all of your bones three times in the injury log. 
You can check the injury log in your backpack to keep track of what you need to break 
and how many more times you need to break it. An easy way to do this is to go to the 
Mega Ramp at the X-Games arena. Veer off to the right at the ramp at the bottom of 
the Mega Ramp into the street area doing a Christ Air.