Cut a styrofoam cup in half, keeping the bottom and discarding the top. Poke the spindle of your turntable through the bottom of the cup and affix a soda straw to it. Put a record on the newly extended spindle.
Now remove the headshell from the tone arm so that you can work on the cartridge. Remove the cartridge from the headshell and reattach it to the other side so that you can attach the headshell to the tone arm with the stylus pointing up away from the platter.
Move the counterweight back away from the fulcrum until it overweighs the tonearm/headshell/cartridge assembly. Start the turntable and let the stylus 'float' up into the groove.
Your record will play backwards and upside down.