http://www.jonpeters.com/ I was going to buy a ping-pong table, but then I decided to build one on my own.
I used two sheets of 1/2 Baltic birch plywood for the table because its sold in 5ft x 5ft sheets and ping pong tables measure 5ft x 9ft.

Baltic birch plywood will be a special order from most lumber yards, and it shouldn't take more than 3 days to arrive, see if the lumber yard will cross cut it, if yes then get it cross cut. After the plywood is cut, you're basically done, but I do a little more work to make it nicer looking and sturdier. I use 1 x 2 pieces of poplar wood to help brace the table and prevent warping. Measure and mark where you need to drill holes, and then pre drill the holes with a counter synch bit. Use 1-¼ inch screws to attach the 1 x 2's to the table. To fill the holes on the tabletop, I use a special bit in my drill press. The wood is mahogany. Once done hammer them into the holes with glue. when the glue dries, saw off the tops of the plugs with a pull saw.
Once the tables are sanded, they are ready for a finish
I use a blue paint for boundary lines
I use 3 coats of water born polyurethane on the top of the table, and I sanded after each coat. Now attach the two halves of the table together using a piano hinge