My entry started as a Bb clarinet duet using a tone set, F,G,A,B,Bb,Db,Eb,E chosen for no especially deep reason. But I switched to clarinet and viola for a more interesting timbre combination which put Cb's into the viola part. For those who insist on a suggestive title, this piece could be called "Bitter Memories". I later added a livelier section (not using a tone set) after the slow initial section so this name may no longer apply - a simple "Clarinet Viola Duet" should suffice.
The midi file is total garbage - sounds like two tone-deaf bumblebees having a fight - might be good for lease breaking. The mp3 is at
http://members.shaw.ca/wreck/mp3/ClarinetViolaDuet.mp3