Officially Licensed National Lampoon's Christmas Vacation Pajamas Includes shirt and pants Pajamas sleep. Cozy and comfortable for winter Unisex Fit. See size chart for additional sizing information. Now you can dress up just like Chevy Chase from National Lampoon's Christmas Vacation when you wear this hilarious and officially licensed National Lampoon's movie Pajamas this year around the house while you're enjoying your favorite holiday movie or fending off your annoying family who are overstaying their welcome.? These National Lampoon's Christmas Vacation Holiday Pajamas are the perfect way to not only show your love for the Chevy Chase 1980s-movie but also show off your holiday Christmas glee - they'll make you feel as tipsy as one of Santa's elves on Christmas morning.