Go up to one and use it it will say 'card read error', press action again and it will say 'Feed me a stray cat' - it works on both of them but it won't repeat again. In the Duke Nukem's 'Titty City' chapter, there are two ATM machines, one near the bar and one near the slot machines in the game room.
Outside of Challenges, all points are doubled in Overdrive Mode. Get to Level 40 in multiplayer to unlock Overdrive Mode.
