I liked when MaryAnn turns into Ginger. Also, the Eva Grump episode.
The one with Kurt Russell as a jungle boy, and the one where they musicalize "Hamlet" for Phil Silvers.
I love asking kids (in front of their parents) if they know who Gilligan was. The parents are usually surprised that the kids have no clue who that is.
Watching the reruns as a kid, my first crush was Maryann. Way before I had any inkling that I was gay.
Radioactive Vegetables is far and away my #1 episode. Just for the bit when the Professor says: "Sugar beets! Mrs. Howell kept eating sugar beets! Sugar is energy--I wonder how the vegetables are affecting her!" And then you cut to see Lovey cleaning her hut at a million miles per hour.
"All About Eva Grub" the one where an ugly woman is transformed into Ginger's glamorous lookalike.
The one about mysterious love letters written to Lovey Howell was good.
The one about mind-reading seeds.
The one about radioactive vegetable seeds.
And the one about a mad scientist who takes the castaways to his island and puts their minds into each other's bodies.
I like the eps where they parodied Dracula and James Bond.