Here is an Ornette Coleman video described as "Free Jazz" from 1978 - Edit 1
Before modification by The_Muted_Grimaud at 19/03/2012 04:42:22 AM
Gimme an example.
It actually works for me going to about the 2 minute 50 second mark. Once the real improvising starts I just lose all interest.
Notice at the beginning there is no real 'melody' of sorts. A lot of instrumental jazz starts with a very obvious melody, which is followed by improvising on the chords of that melody. Here they sort of start with a vamp on the Rite of Spring opening bassoon theme. (no joke). Then the drummer does some 'free improv' stuff that just destroys the groove
' /> ... then they do more of the opening theme idea ... then more groove destruction ... then they take the opening theme idea into complete improvisation (and cacophony). This is where it starts to sound like other free jazz concerts I've been to, and it's really horrible ... for me. 
scary part is this is 1 of 3 videos, is that to say this free jazz solo lasts a half an hour?