This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
As for what happened at today's year end party, I'll just let it go.
I'm already really forgetful, so I don't need a so-called "forget the year party."
In many Japanese companies, new workers are required to do a short performance at an end of the year party.