How to build an insulating attic stair box

During my home energy audit last winter, we discovered that my pull-down stairs are poorly sealed and insulated, therefore it'd be a good idea to build an attic stair box to keep the conditioned air from escaping into the attic.  Rather than pay $200 for a contractor to do it, I recruited a few friends to help.

4' x 8' Foam board insulation from Home Depot (3" thick = R-13):  $25
bits of wire hanger to connect pieces:  free from dry-cleaner
duct tape to secure edges $5
Total cost of materials:  $30

Annual heating and cooling cost savings:  to be determined next winter

Satisfaction of building it with friends:  priceless!

Thanks to the attic stair box construction team, clockwise from top left:  Construction Skills, Project Manager, General Mischief, Artistic Direction/Photography.