Ever try to fill a glass or cup from a portable water cooler? You need to move the cooler to the edge of the table right? Let's fix that.
Step 1: Measure your cooler
Create a layout/drawing such as the one shown here, our you can just download our .DXF and .PDF (cooler.zip)
The two parts you make will be identical, except for the center slot. One part will have a slot (the width of your board) from the top, to just past the center, and the other part will have a slot from the bottom, to just past the center. This will let them nest together.
Tip: Be sure to measure your panel (plywood, MDF, etc.). Just because you bought 3/4" plywood, doesn't mean it measures exactly 0.750 inches, right? If the fit is important, measure the material, and adjust your design accordingly.