1. The time of day at which there is a spike in the amount of nOObz online. Generally one will see a sharp increase of nOOb encounters around 3:45, Monday through Friday, due to the end of the school day. nOOb-thirty occurs for the better part of a whole weekend as well.
2. This can also be an expression used by a skilled gamer to let other gamers know s/he is now online.
1. Bobby: What the F**K, that is the 6th time in a row I've been killed by a grenade launcher!!!
Tommy: Bobby, check the time....
Bobby: Aww shit, it's nOOb-thirty already?
2. Hastro: Guess what bitches...it's nOOb-thirty, get ready to be pwned!!!