During Project OXCART (development of the Lockheed A-12 "Blackbird"), recreational facilities at Area 51 included a gymnasium, movie theatre, nine-hole golf course, and a softball diamond.
The Area 51 softball team was called the 8-Ballers. They played against such teams as the NTS Mototr Pool "Truckers" and Area 12 "Mets."
"The Bulletin Board," an unclassified newsletter published by Reynolds Electrical & Engineering Company (REECo) for Nevada Test Site (NTS) employees regularly posted articles about Test Site sporting events. Throughout the 1960s, headlines such as "Area 51 Wins Slow-Pitch Tournament" were common and many of the players were listed by name.
Google Earth photo of the softball diamond.