Yesterday, my employer took me and 50 other team members to see the new Star Wars movie! During office hours! All paid for by the company!
They just sent us a letter saying: "thanks for coming". I want to write back: "thanks for forfeiting company time and buying us tickets!" or: "thank you for this christmas gift"
Maybe the word I am looking for is "Gesture"? ("Thank you for this kind gesture and for organizing a great movie event")