Cream Lemon is probably the single most widely spread adult animation ever created. It started in 1984 with the very first installment of the Nonomura Ami series, called Be My Baby. When Cream Lemon was created, there had never been anything like it. In fact, the seiyuu who does Ami-chan's voice (Oikawa Hitomi) said that no one knew how she was supposed to do the various sex scenes, so they rented a bunch of pornographic videos, went to the director's place, and watched porno movies so that she could do the part right (she also mentioned that she originally used to get out of breath occasionally, but that she's used to it, now ^_^).
Cream Lemon itself is a series of (more or less) stand-alone OVA stories, ranging from shoujo drama (Nonomura Ami series) to parody/comedy (Pop Chaser), to fantasy (Rall) to horror/suspense (Black Cat Mansion), to science-fiction (Star Trap). The intent was to try to reproduce in anime what many countries do with their various "art films". To this end, Cream Lemon uses many instrumental pieces of music for BGM that either are, or are inspired by, classical arrangements. Cream Lemon was also intended to offer adult spoofs of various popular genres (for example, Star Trap spoofs the Dirty Pair series as well as various other sci-fi shows & stories). You COULD say that Cream Lemon explored the "what if..." possibilities (i.e. "What if this happened, instead?") and did it (mostly) very well.
Not exactly the first Hentai anime ever, this one was the first to introduce the concept of an actual STORY to the hentai. Several of the stories are hentai parodies, and quite amusing. Some are serious, and are actually interesting. Thanks to Cream Lemon we now have excellent adult works like End Of Summer and First Loves. The animation isnít the greatest ever (it was done in the mid 80ís) and the music is tolerable, but what makes nearly all of Cream Lemon so entertaining is the interesting narrative. If you can appreciate Adult Anime at all, you really should see at least one episode of Cream Lemon, as you will almost certainly enjoy it.
Currently only available fansubbed.