You're done your pumpkin! Now it's time to shut off the lights, or take it outside in the dark, and check out the beams. To make the beams more visible you can use fog or smoke. Fog can be purchased in a spray can, or you could borrow/rent a fog machine for continuous enjoyment. Or, you can set up some incense to burn allowing the smoke to pass through the laser beams. Keep in mind that the wind will blow your smoke in certain directions, so try and set up you fog or smoke to be blown into the beams.
Laser beams will project out for long distances, so be sure not to shine your laser pumpkin anywhere that might affect other people's vision. Beware of cars, planes, and your neighbours.