Snowball Sunday is a winter/Christmas-themed snowball fight game for the Commodore 64, written by Ashley Routledge and David Saunders. There isn’t much information available about it online, but from what I can tell it was given away free with various Commodore magazines in 1988. It was also freely available for download from Compunet (aka CNet) – an interactive service provider that was accessed via dial-up, that existed from 1984 to 1993.