Two and a Half Men
A full list of special holiday episodes

Two and a Half Men
12 seasons, 2003–2015
This sitcom follows the lives of two brothers, one a carefree bachelor and the other a divorced father, as they raise the latter's son together.
The show aired 7 Christmas episodes, 1 Thanksgiving episode, 2 Halloween episodes, and 3 Valentine's Day episodes.
Christmas episodes:

Season 3, Episode 11
Santa's Village of the Damned
Alan's girlfriend Sandy is a great cook and homemaker, which leads to Charlie and Alan gaining weight from her delicious meals. However, her increasingly erratic behavior becomes too much for them to handle.

Season 4, Episode 11
Walnuts and Demerol
Charlie's attempts to have a one-night stand on Christmas Eve are jeopardized when his family and friends unexpectedly show up at his house and refuse to leave.

Season 7, Episode 11
Warning, It's Dirty
Charlie goes against Alan's wishes and urges Jake to pursue a girl he met on the beach, while his girlfriend is away for Christmas.

Season 9, Episode 12
One False Move, Zimbabwe!
During Christmas, Walden's mother comes to visit and Alan develops a crush on her. However, she reveals a dark secret about Walden's past involving a pet, which sends him into an emotional breakdown.

Season 10, Episode 11
Give Santa a Tail-Hole
Walden poses as a Christmas tree salesman and unexpectedly receives a business proposal from Mark Zuckerberg. Meanwhile, Alan is left alone at the beach house during the holiday season.

Season 11, Episode 10
On Vodka, on Soda, on Blender, on Mixer!
Walden aids Jenny in securing a second date with a woman who is avoiding her, while Alan is propositioned by his girlfriend's ex-partner.

Season 12, Episode 8
Family, Buble, Deep-Fried Turkey
Walden tries to restore Louis' Christmas spirit, but faces obstacles from Alan's mom and Alan's frugality.
Thanksgiving episodes:

Season 1, Episode 10
Merry Thanksgiving
Charlie tries to host a traditional Thanksgiving dinner, but has to bribe his family members to attend. The usual family conflicts arise and tensions escalate. Judith's parents disapprove of their daughter's relationship with a woman.
Halloween episodes:

Season 3, Episode 6
Hi, Mr. Horned One
Charlie's girlfriend, who is a Satan-worshiper, has a talent for the supernatural, and some strange occurrences are taking place around the Harper household.

Season 12, Episode 1
The Ol' Mexican Spinach
On Halloween, Walden faces a health scare that prompts him to reassess his priorities with Alan's support.
St. Valentine's Day episodes:

Season 6, Episode 15
I'd Like to Start with the Cat
Charlie's careless words and inattention to details result in him and his girlfriend being sent to couples counseling.

Season 9, Episode 16
Sips, Sonnets and Sodomy
Alan and Walden's Valentine's Day plans are ruined when a heavy storm traps them at home with their bickering girlfriends.

Season 10, Episode 16
Advantage: Fat, Flying Baby
Walden hopes for a Valentine's date with Kate but she only wants to be friends. Alan tries to impress Lyndsey but ends up in the hospital. Rose lures Kate to China for a business deal.