XSp.

You learn something new/incredible everyday… 😀
Studio Gainax, one of the most sucessful and renowed japanese animation studios (Neon Genesis Evangelion, KareKano, FLCL, Tengen Toppa Gurren Lagann, Mahoromatic, Nadia – The Secret of Blue Water), had their start with a couple of videos known as Daicon III and Daicon IV:

They were made as promo for the 22nd DAICON Nihon SF Taikai, an anime and sci-fi event back in 1983. Five years later, in 1988, a Laserdisc version was released and sold for about $200 bucks. But today, if you can find a copy, you’d certainly get at least some $1500 for it.
Actually, because of Copyright infringements Gainax was not allowed to sell it (namely the Playboy bunny girl costume, and the famous music from Electric Light Orchestra), so they bundled it as a bonus with a production artbook.
For those who watched Densha Otoko, now you know where the opening, Minna, and the music from the opening came from. For those who didn’t, DO IT NOW! 😛
The video I posted there is an HD remastered version of the Laserdisc one.
Awesome! Very very awesome! I actually got a little teary eyed… ;_;

Source: SankakuComplex (NSFW)