This is "inverted contrast" or "reverse contrast" lettering.
Didn't find this as a font but still looking.
A less extreme similar font: Signo http://www.myfonts.com/fonts/r-type/signo/
The best known reverse contrast font is Antique Olive http://www.myfonts.com/fonts/linotype/antique-olive/
Some that are more extreme: ITC Zipper http://www.myfonts.com/fonts/itc/zipper/
Stretto http://www.myfonts.com/fonts/canadatype/stretto/
Don

Also: FF Balance http://www.myfonts.com/fonts/fontfont/ff-balance/
Don

Can't identify it. Custom maybe... One alternative but far from being even loosely similar: Squish

This is by one of the designers at a great little foundry called OrType, closest font they have for sale is La Pontaise

http://ortype.is/specimen/la_pontaise/i9b3mA6ghojxSMNHs

La Pontaise is not reverse contrast like the mystery letters.
Perhaps you are referring to another font?
Very confusing site.
Don

This is a custom typeface designed by Mads Freund Brunse for this specific series of events in Copenhagen. Maybe one day we might release it on www.ortype.is !

Thanks for sharing the info on Mads Freund Brunse. I find his custom typeface fits together well and is more attractive than most reverse contrast fonts. I don't know whether it was intended to evoke the rhythms of boogie-woogie music but the letters seem to suggest a bouncy theme without resorting to an irregular baseline.
Are any more letters available for viewing?
Don