This is great fun in warm weather at a campfire, and it takes a little practice for the perpetrators. There is plenty of room for variation, depending on what the Scouts can imagine and how the volunteers react at the time. As usual, the Scapegoat gets wet.
You will need an Announcer and a Pitcher, but the Batters will be volunteers. The first Volunteer should be told what is happening ahead of time, so that his performance shows others how it's done. Set up a sheet a backdrop. Two Scouts hide behind it, one with a flashlight and the other with a bucket of water (but be sure that the audience does not see the bucket). The flashlight is held against the sheet to simulate the ball. The movement of the light is the key to the whole skit.
A baseball bat or a thick stick is needed for the batter, and a baseball glove for the Pitcher. Use a roll of canvas and a stick (or something similar) to simulate the sound of the ball hitting the catcher's glove (done by a Scout behind the sheet). If it is dark, have two strong flashlights shining on the Pitcher and Batter.
The Announcer comes on stage and tells the audience that there will be a baseball pitching demonstration. He introduces the Pitcher as the greatest pitcher of all time, who will show us his famous specialty pitches. After a buildup about how great the Pitcher is, the Announcer positions the Pitcher at one end of the sheet.
The Announcer asks for members of the audience to volunteer to try to hit this famous pitcher's best pitches. The first volunteer is given the bat and placed at the other end of the sheet. The Announcer explains that the Pitcher will throw one pitch, and the Batter must do his best to hit the ball.
The Pitcher winds up and pretends to throw, as the Announcer narrates ("He's set. He winds up. There's the pitch!" The Scout behind the screen moves his light rapidly down the sheet. The Announcer yells, "Fast ball!" The Batter swings hard. We hear the sound of the ball hitting the catcher's mitt. The Announcer says, "A strike! You're Out!" The Batter returns to his seat.
Another Batter is recruited. This time the Announcer calls out a curve ball, which curves wildly across the sheet. The Batter is again called out. The process continues with a knuckleball and a screwball.
Finally, the Announcer introduces the famous Pitcher's dreaded Secret Pitch. He asks for a special volunteer, of especially outstanding baseball ability and unusual courage, to try to hit this pitch. A Scapegoat is volunteered by the Announcer and encouraged to come up.
The Batter is carefully placed, and the ball is pitched. As it comes to the Batter, the Announcer cries, "Watch out! It's a spitball!"
His warning comes too late, as water cascades over the sheet onto the Batter.