20 October 2004: The Melody of Oblivion
Episode 15 of The Melody of Oblivion contained a Daicon reference.
This is not the first time a Gainax show has paid homage to this Daicon icon. As you'll recall, FLCL had Haruko sky-surfing on her bass while wearing a similar outfit.
For the record, Playboy bunnies sky-surfing on huge broadswords and fighting giant robots is like the best idea, ever.