The Konami Code, noclip, godmode, big head mode, there are tons of cheats in games new and old, but what is your personal favorite?

There is a special place in my heart for the Nail Gun cheat in IO Interactive's Freedom Fighters. Basically every bullet acted as a nail and after death, the enemies would shoot straight back along the trajectory and then pin to the wall/vehicle/object at the end of that path. That combined with the Flymo Ragdoll cheat was ALWAYS a lough-out-loud good time.