Jak 2 Renegade Cheats :
WaLl Glitch/Stadium Glitch
you need to use any type of Hover-ships definitely a small fast one. go to the Place near the stadium, look in the map to find it. go to the right wall(maybe left?) nearest to the stadium, go through it, you'll see you are through the wall and BUT don't try to go up yet, explore and you'll be underneath the stadium, go up and you wonder''where am I?''