The state of unpleasantness that follows a night of heavy binge drinking. The effects of a yesterfester can include but are not limited to the following:

Beer Farts, Headache, Beer Shits, Puking in one's own bed, Lost articles of clothing, personal items or friends, Heartburn, Nausea, Indigestion, Yay Pepto Bismol!, Feelings of Helplessness, Waking up to a toothless woman or dude, being lost, and losing your identity.

Part of the overall experience of a yesterfester is piecing together the events of the previous night that lead up to the yesterfester. Yesterfesters are often the result of a yesterfest.