The holiday celebrating when the lord came down and gave food to the people but was rejected by them. They said it was too much so he took a great sum back and the people only got to eat small portions. This holiday is celebrated by having small portions of food for breakfast, lunch, and dinner. The day it is celebrated on is the last Sunday of November.
A: Dude, lets go get a massive amount of food!
B: No way! It's Yimidum meaning we eat small portions!