I mentioned this before in Ramble On I think, but a friend of mine sent me a Pink Floyd boot from Philadelphia in 1987 and included was a bonus disc of a soundcheck they did in Austria in 1988 and during one of the random jams they were doing on stage, one of them turned into Heartbreaker.....and not Pat Benatar's version. It was probably the opening riff and maybe part of the 1st verse, but it was trippy hearing David Gilmour playing something Jimmy Page wrote as I don't think Page ever did any jamming and incorporated Pink Floyd into it.
It was pretty neat, anyway. Apparently there's a clip of them doing Good Times, Bad Times as well but I don't know how verifiable that is; none of my usual bootleg contacts have heard of it.