The term 'ROLLERBALLS, E.G.' is an example of a type of ball game that involves rolling a ball along a flat surface. The crossword solution for this term is 'PENS', which is an acronym for 'Pavement Entertainment Skating'. This type of game is typically played on a flat surface such as a sidewalk or street, and involves rolling a ball along the surface while performing tricks. It is a popular form of recreation among skateboarders and other extreme sports enthusiasts.