“Live Show” (2010)
Liz is upset because nobody remembers her 40th birthday, Jack tries to give up drinking to support his pregnant girlfriend, and Tracy threatens to break character during TGS.
Looking for the Birthday episodes of 30 Rock? Here's the complete list, all 4 of them, with season and episode numbers so you can jump straight to the right one, plus a quick note on why each is worth your evening.
Liz is upset because nobody remembers her 40th birthday, Jack tries to give up drinking to support his pregnant girlfriend, and Tracy threatens to break character during TGS.
Liz, Jack and Jenna rub elbows with the upper crust at a prince's (Paul Reubens) birthday party. But the end of the evening finds Liz lying low after Jack's ex-wife (Isabella Rossellini) shows up.
While Jack plans the perfect 50th birthday party for himself, he watches old home videos that inspire him to recreate one of the happiest moments he had a young boy. Liz's ex-boyfriend Dennis decides to come clean about an addiction, stirring up drama between Liz and Jenna.
Liz befriends a pregnant teen in an attempt to adopt her baby. Jenna vies for more attention but Kenneth's plan to combine her birthday party with one for Tracy derails her efforts. Jack goes out with the guys and bonds with Frank over daddy issues.
There are 4 Birthday episodes of 30 Rock, from “Black Tie” (S01E12, 2007) through “Live Show” (S05E04, 2010).
A good place to start is “Live Show” (S05E04, 2010). Liz is upset because nobody remembers her 40th birthday, Jack tries to give up drinking to support his pregnant girlfriend, and Tracy threatens to break character during TGS.
The most recent is “Live Show” (S05E04, 2010).
They're spread across 3 seasons, from season 1 to season 5.