mkv
 

my buddys got this video file as an mkv
i dunno what that is
how do i convert that to an avi?

Its a Matroska Video container file, a bit like avi, but it supports multiple video, audio and subtitle streams all in one file.

Read here to get an idea on how to playback Matroska files.

o awesome
is there any way to convert them to avis?

'course there is, its just you might run into some problems.

Try VDubMod for starters.