Tony Hawk's Underground 2 Cheats :
BlOw stuff up
During the 'Boston' level in THU2 go through the trash can that is on fire and grind over both the cannons opposite the construction site they will fire and the construction site will fall.
In the triangle find the crashed helicopter with the missiles and grind the missile it will blow up half the mountain range
Hope this helped
MASSIVE Air in Bracelona
Get any character that has max stars in every stat. Go to Barcelona and jump into the catapult. You should go onto a building. Face East of where you are standing and get some speed now spine transfer(R2)then again and again and then there is a fan boost release the x button and you should get some big air!