In the past I have posted on Anjani and Madeleine Peyroux, who have recorded wonderful jazz interpretations of Leonard Cohen and, in Peyroux's case, other singer-songwriters: Bob Dylan, Joni Mitchell, and others. Likewise, Cassandra Wilson has jazzified rock musicians from Neil Young to U2. And, decades ago, Ella Fitzgerald recorded The Beatles.
It seems regrettable to me that the original artists did not directly experiment with jazz forms. Joni Mitchell was an exception: she went through a jazz phase in the late 1970s, recording with Jaco Pastorius, Pat Metheny, Michael Brecker, and others. More jazz-rock than jazz, but still. When it works, it's brilliant.
Cohen, on the other hand, avoided jazz, and liked to police his musicians against jazz intrusions... or did he?
Here's an astounding video of Cohen and Sonny Rollins playing "Who by fire" (spotted on HuffPo). It made my day. I wonder if more such exist.
Update: fixed jazz police link