1. The act of getting hammered on a fun night out with the ladies, when everyone else is only having a few sociable drinks.
(The Gandolfer will include making a fool of themselves, relying on others to stand, finishing everyones drinks, puking, going home with randoms/inviting randoms to their friends' houses, getting rowdy, puking anywhere, and perhaps keeping everyone up in the night.)
2. Someone who is a borderline alcoholic, and only hangs out with friends if they have booze and/or weed. Their lives tend to revolve around these substances.
1. "ooohh looks like crystal is pulling a huge gandolf tonight, ughhhh"
2. "Miranda is such a gandolf, she needs to go to aa soon."