If you read the code, it seems to suggest this is just the (fun) name of the lit display driving code.
Re:Apollo program source code
by mladenkovacevic on Wednesday April 25, 2012 @10:24AM
(#3889213)
I believe pinball was the name of their keyboard and display program (not an actual pinball machine)
http://www.ibiblio.org/apollo/listings/Luminary099/PINBALL_G...
It's in the code repository for multiple Apollo's