The Clean Room Infiltration

"" is the fifth Christmas-themed episode of the television series The Big Bang Theory, originally aired as the eleventh episode of the show's eighth season, on December 11, 2014.

Plot
Amy hosts a traditional English Victorian Christmas Eve dinner for the gang while the guys are conducting an experiment in the university clean room and accidentally let a bird in. To prove a point to Amy, a Scrooge-like Sheldon buys her the perfect gift to ruin her Christmas.