all you do is take some broken crayons (and what mom doesn't have oodles of those?!) and stack them on top of the pumpkin.
Then take your blow dryer and depending on how big of hurry you are in you can either put it on low or high (but if the crayons are small the high will blow them off and then they will melt on the counter....) Let the wax drip wherever but you may need to tilt the pumpkin to help it run down. Make sure and have a stack of newspaper underneath to catch the wax. Or better yet, grab an extension cord and do it outside (it was raining when we did it so I couldn't).
I think the bigger ones would turn out awesome!