My Great Grandfather, his brother and a cousin were in the Great Snowball Fight of Jan. 29, 1863 in the Rappahannock Valley, northern Virginia. Texas, Arkansas, and Alabama troops were involved. There may have been other units involved.
Other noted snowball fights were: Dalton, Ga. 22 March, 1864 - Fredericksburg, Va 23 Feb,1863 - winter camp Orange Court House, Va 23 March, 1863 or 64 (not sure on the year with out looking it up). I'm sure there were many more than listed here.