A holiday traditionally celebrated upon the second snowfall of the new year, usually falling sometime in the first two weeks of January.
The Yamball holiday is observed by building a "yamball" out of a mixture of flour and canned sweet potatoes ("yams"). The ideal yamball has a playdough-like consistency and is slightly smaller than a junior basketball (~6 or 7 inches in diameter).
The yamball is then thrown back and forth by the celebrants until everyone is properly tired out, at which point there is a yamball "toss" which is performed much like an egg tossing contest (i.e. subsequent tosses must be from increasingly great distances).
The yamball is then retired to a front porch or other outdoor area. After a few days, if the Skunk King Wenceslaus is pleased with the yamball, He will leave gifts nearby for the children of the household.
Traditionally Yamball was also celebrated by holding a formal ball known as the "Yamball Gambol" but this is seldom practiced in modern times.
Yamball is now often used as an occasion to exchange gifts with friends who have spent the December holiday season apart due to family obligations.
Tom: "Hey what did you get Harry for yamball this year?"
Dick: "I couldn't think of anything so I just got him more yams =/"