One guy, five girls, a mountain hideaway, hot springs, some incest... hentai? hentai? hentai? No, it's Tenchi! Tenchi Masaki is the kind of anime main character that every frustrated young man dreams to be: the one guy who all the girls are after. Of course, all those young men in the audience are constantly frustrated by Tenchi's inability to just choose one and settle down, but then, if he does that, the story ends and there's no more Tenchi. This OAV is just the beginning. There's lots of Tenchi TV, and movie after movie (I hear the final movie has been released where he finally realizes that he's gotta make his decision, or else).
Aside from Tenchi's sexual na´vetÚ on the surface, Tenchi Muyo! seems mostly to be about finding out how much we need nature. Tenchi and gang are happiest in their peaceful home by the lake, farming carrots for Ryo-Ohki. The Jurai have the technology to control the weather, but without an uncontrolled rainstorm, Ayeka might not have come to love Tenchi. Also, you might notice that much of the technology in Tenchi's universe is mixed with nature. Jurai spacecraft center around a single powerful tree. When Ryo-Ohki is not a spacecraft, it's a cute little mascot cabbit.
If you think that a lot of Tenchi doesn't make much sense, you're right. The very name "Tenchi Muyo" means "No Need for Tenchi". The kanji is Ten, meaning heaven, and Chi, meaning Earth. One use of this is to put them both on a box being shipped, such that heaven goes up and earth goes down. It's kind of a "This Side Up" mark, but in this anime, there's no need for Tenchi. There's no set way to look at it. On first viewing it, you probably won't know what to make of all the crazy romantic comedy going on, so sit down, keep your eyes peeled, and be ready for all the fun and action in Tenchi Muyo!