tiny windowsill bugs
Sorry for the delay. I conferred with a colleague and the consensus is that they are Sciarids, a type of fungus gnat fly. Fungus gnats often live in the soil of houseplants where they feed on organic matter or, if very numerous, on roots. They are attracted to light at the window.
It is not possible to provide an absolute identification from a photo so we use characteristics like the tilt of the body, skinny outline, etc. To be positive we'd need specimens mailed or brought to us at WSU Extension, 600 128th St SE, Everett, WA 98208/
Have a look at Bradysia praecox on the page at http://www.commanster.eu/commanster/Insects/Flies/Sciaridae.html to see if you agree.