just say some new bands that you really believe are good (and you hope are going to be big) its better if you dont plug your best mates band, but someone youve heard and you thought were really good. the size of the band at the moment neednt matter, they could be unsigned or getting minor music tv/radio play.
if they have a website as well post that, or post somewhere you can download their music for free.
Duke Raoul
http://www.drownedinsound.com/articles/11147.html

tom vek - http://www.tomvek.tv/,
http://www.bbc.co.uk/dna/collective/A3440774