The 13-piece Homerun Challenge Set comes with a bat, 4 balls, homeplate, pitcher's mound and six marker cones to set up an outfield fence. The package has instructions for 4 unique games, including Junk Ball Baseball, Ghost-Runner Baseball for two kids and imaginary runners and RBI zone baseball. Junk Ball is an amazing new plastic baseball with an adjustable dial and scuff marks that cause the ball to curve, slide, and knuckle.  It makes it easy for anyone from 5 to 55  to throw all kinds of big league “junk” pitches.  The ball is aerodynamically designed to move in the direction of the scuff marks.  The Junk Ball bat is designed with a large “sweet spot” to drive the ball further when it is hit.  Junk ball is safe to play in backyards. Homerun Challenge began shipping in March 2006.