This is the movie that Rory, Dean, Lane, and Todd go to see on their double date at the Black-White-Read Bookstore.
Attack of the 50 Foot Woman is a 1958 science fiction film directed by Nathan H. Juran (credited as Nathan Hertz), and with Allison Hayes in the title role. It is about a beautiful but rather unstable socialite who increases to a gigantic size after contact with a mysterious alien figure. She uses her new stature to take revenge on her cheating husband.
Made on a very low budget, Attack of the 50 Foot Woman is a technically “bad” sci-fi movie that is fun to watch, and has become a camp classic.
The joke is that they are watching a film about a giant woman while Lorelai is on a double date with Jackson’s cousin Rune, who thinks she is too tall, and acts as if she is freakishly huge.
(A movie date is not really suitable for Lane’s purposes, since she wants to talk to Todd and get to know him better. I’m guessing Lane and Rory chose the cinema as a way to hide from Mrs. Kim – if they went for coffee at the diner or just strolled around town together, there was a higher chance of being spotted. Luckily, Lane only needed a couple of very brief chats with Todd to learn all that she needed to know about him).