How do i get the other black ops zombies maps?

i have dead ops and five but there are other ones in the leader boards how do i get them?How do i get the other black ops zombies maps?
There is dead ops arcade, watch this to find out how to unlock it:

http://www.youtube.com/watch?v=akSfM_1Vj鈥?/a>How do i get the other black ops zombies maps?
Go to playstation store/Xbox equivalent, and search Black Ops/Zombies, the four maps are the maps from World at War, you could also have got it from the Hardened or Prestige version of Black Ops

money games

just tires