1. Leave It to Beaver—"The Haircut"

 

First aired: October 25, 1957

Beaver has always struggled to hold onto money, and in the episode "The Haircut," it almost leads him to lose his Christmas spirit, too! You see, this time the funds Beaver misplaces were for a haircut, so he can look extra-sharp as an angel in the boys' Christmas choir. To solve his problem, Beaver gives himself a haircut, and it's, as you might expect, a disaster.

Most of the episode focuses on Beaver's and Wally's attempts to conceal Beaver's shocking mohawk from their parents, which skews a little naughty on Santa's radar. The episode barely mentions the festive season, but finishes with the set all decked out so we know exactly what time it is: Christmastime. It all ends in this classic shot, showing Beaver's "solution":

2. Lost in Space—"The Toymaker"

 

First aired: January 25, 1967

For the Lost in Space episode "The Toymaker," the setting of Santa's workshop gets a sinister twist. Rather than bring St. Nick himself, the episode introduces "O.M.," an old man who traps Dr. Smith and Will inside a robot where the toymaker's workshop is. As Smith and Will try to find a way to escape from the toymaker—who's decided to turn them both into toys—they come upon a boarded up window that shows them a view of Earth at Christmastime.

Between this scene and the colorful episode setting featuring giant nutcrackers, our secret Christmas episode alarms were going off like "Jingle Bells."

3. Happy Days—"Tell It to the Marines"

 

First aired: December 16, 1975

The only hint for viewers that the Happy Days episode "Tell It to the Marines" is a Christmas episode was the air date. Premiering the week before Christmas 1975, the episode finds Ralph dismayed to be dumped and turning to Fonzie for help. Fonz's surprising advice? He tells Ralph to join the Marines.

Ralph runs with Fonzie's advice, and now Richie's the one who's upset. He decides to convince the Fonz to talk Ralph out of it. Richie tracks down the Fonz at the diner, and this is when the Christmas spirit really invades the episode. Richie finds Fonz posing for his annual Christmas photo, pictured here. In the end, Fonzie convinces Ralph of the real moral of the story: To be truly happy, you have to find someone who loves you for who you are.

4. Batman—"The Duo Is Slumming"

 

First aired: December 22, 1966

Here's another classic Christmas episode you'd only expect to be festive because of when it aired on TV. The second season Batman episode "The Duo Is Slumming" pits Batman and Robin against the Puzzler, who hopes to slow down the good guys by giving them a mystery to solve. When Batman and Robin easily solve his puzzles, it ends in a battle in an old balloon factory.

So where does Christmas come into this, you're wondering? It's in the form of a window cameo from popular Western actor Andy Devine as Santa, who pops out and gets a proper welcome to Gotham City by Batman himself. Santa immediately asks for the secret location of the Batcave to drop off something in Batman's stocking, and Adam West turns to the viewers and asks, "If you can't trust Santa, whom can you trust?" The minute-long tangent is a delightful bonus gift for TV audiences the week of Christmas 1966.

5. Cheers—"The Spy Who Came in for a Cold One"

 

First aired: December 16, 1982

Christmas isn't so much a secret in the Cheers episode "The Spy Who Came in for a Cold One" as much as it is a rich background element of this nontraditional Christmas episode. The opening shot showw a wreath on the bar door, which Norm throws open to reveal the whole bar is decked out, as are all the bartenders. Even Carla's got her Christmas pin on, taking a page from Diane's book for once!

The plot ignores Christmas altogether, though. It's focused on an exchange between a man in the bar who claims to be a spy and Diane's eagerness to prove he is a liar. Everyone else in the bar immediately gets wrapped up in the customer's little Christmas white lie. Once Diane exposes the fraud, though, the man gets back at her by selling her on other stories, leaving it up to us to decide what's real and what's not.

6. The Twilight Zone—"Five Characters in Search of an Exit"

 

First aired: December 22, 1961

The Twilight Zone episode "Five Characters in Search of an Exit" is a classic, and its memorable plot twist in the end is tangled in Christmas tinsel. It's what makes it possibly the best secret Christmas episode ever made.

The episode follows five characters, a clown, hobo, ballerina, bagpipe player and a soldier. They're all trapped in a room that has no door to leave through. As the claustrophobia gets to all of them, the shot eventually fades out to reveal that they are all toys that were dropped in a Christmas charity donation barrel for orphans.

It's one of the greatest reveals in Twilight Zone history, and for those who revisit the episode each Christmas, it's the gift that keeps on giving, viewing after viewing.