Has anyone read GTO or seen the anime?
I personally have seen the anime only, but I'll take the manga from my brother.(You can find the manga if not here in Animemangafun.com)
It's really really funny.It's one of the best animation I have ever seen.
There is a prequel called BadCompany and you can find it in OneManga.com if u cannot find it here, and there is also a sequel called Shonan Junai Gumi(The Pure Love Gang from Shonan or Shōnan True Love Group). I haven't read that one cuz I haven't searched yet.You can find more info about this in Wikipedia.org
Now Tohru Fujisawa(creator of GTO) is writing Kamen Teacher, which is really good drawn and from what I have read its funny and maybe it will have a good plot too, but I have only read 2 chapters :( .
Speaking of kamens=masks you should also read Ultimate Hentai Kamen, its really funny and has nth to do with sex, instead what the name implies
If you don't find it here that either read it in OneManga.com.