Well since we're talking about unknown bands, I'll promote some portuguese bands. They sing in English, so no problem, everyone will understand what they're singing
These guys are not really unknown around here anymore, but I bet they're unknown pretty much everywhere else in the world lol So here we go.
More Than a Thousand
These guys are great. I think their music is classified as punk, screamo, rock, or whatever lol In their website you can find mp3, so you can listen to them.
Easyway
Another cool band. These guys are making it great, Lagwagon's frontman Joey Cape even has a participation on their last album. They're rock music, punkish, I don't know, pretty cool. You can also download a couple songs from their website, to listen to some more you can go to their page on myspace.
Twentyinchburial
I've already talked about these guys here and put some songs up for download, so I'm kinda repeating myself. They're awesome, so make sure you listen to a couple of their songs.
The Aster
These guys are beginning, and already they're pretty good. I can't wait to see what they'll do next!
Fonzie
I think I've talked about these guys here too, but it's never too much
They're pretty goos too, Nikola Sarcevic (from Millencolin) sings in one of their songs, which is wicked.
So there you go, plenty to check out, and all portuguese bands