do I need to play the original Borderlands in order to be able to understand whats going on in Borderlands 2?
nah, usually when a software developer makes a sequel they don't require you to have played the previous games, it should be good as a standalone although Borderlands 1 was an awesome game so you should try it anyway
Actually, I have played Borderlands 1 when it released and I like it. Now I am waiting for its next series Borderlands 2 that will be release on 18th September, 2012. I saw the trailer of Borderlands 2 and from that trailer I don't think new player need to play previous version to understand coming up next version of Borderlands.