A nightgib is a nerd gathering that takes place at night. The concept of nightgib is to game with your fellow nerds at night time.
Connected to LAN-party.
Joe- Dude! I'm totally in the mood for some WoW, but my dad has banned WoW in our home. He says it will ruin my social skills and my chances to ever find a girlfriend!
Jake- Sure dude, I'm in the zone! Let's go to GameCenter for a legendary nightgib!