Oh. My. God.

I just heard...

the next best thing
after jRock.

FANBOYS!! XD THEY'RE GOOD AT SINGING!! Especially when trying to be Vocaloids!

Sayonara Zetsubou Sensei (not sure which season):

This guy even does the girl voices himself.

And for those who have accounts at Nico Nico Douga...
【ニコニコ動画】「カンタレラ」歌ってみたよんじ。
【ニコニコ動画】カンタレラを歌ってみた【amu】
【ニコニコ動画】「カンタレラ」を歌ってみた。 byチェロス(笑)
【ニコニコ動画】服毒しそうなカンタレラ歌ってみた。＝のど飴
【ニコニコ動画】何も考えずカンタレラを歌ってしまった。Ver.ASK

What they were fandubbing:

If you don't have an account, don't kill yourself trying make one (the site is entirely Japanese [you can make it Chinese though :D]). I can lend you mine... as long as you swear to do good and nothing but good!