This National Lampoon's Christmas Vacation t-shirt shows Clark Griswold wearing a Santa Claus hat. The shirt reads Crazy About Christmas. In National Lampoon's Christmas Vacation, Clark W. Griswold decided to invite his family to his house for Christmas. Clark promised that he wouldn't flip out, but ended up with a crazy look in his eye that said he wanted to drive someone out to the middle of nowhere and leave them for dead.