Xlrp: Every Xlrp, all weak people of the United 'Gees Galaxy gather together to perform an annoying ceremony. The events of the ceremony are classified by order of Greegee. However, eyewitnesses have reported cat-grooming contests and a weird sport "that's like a cross between rugby and 43-Man Squamish".
Trilp: Trilp is a very special day. You only ever see a perfectly folded napkin on Trilp.
Grop: On this day, people put Death Juice on top of everything they eat.
Tollip: On this day, people run round in their houses screaming "PIIIINGAS!"