Softball is a sport, similar to baseball but with a larger ball and smaller field.
In February 2274, during shore leave at Hus-24, Hikaru Sulu accepted an offer from a reptilian officer to play a game of softball. Members of the crews of the USS Venture and USS Enterprise enjoyed the game. (TOS comic: "Husian Gambit")
In 2368, Turrok altered a holodeck program featuring a park in Ohio, one originally written by Worf. The new version of the program misrepresented Klingons, showing them playing softball, throwing Frisbees and having picnics in the park. (TNG novel: War Drums)
- According to his biography, novelist David R. George III enjoys playing softball with his wife. (TLE novel: Serpents Among the Ruins, DS9 - Mission Gamma novel: Twilight)