These 16,000 BBC Sound Effects are made available by the BBC in WAV format to download for use under the terms of the RemArc Licence. The Sound Effects are BBC copyright, but they may be used for personal, educational or research purposes, as detailed in the license.
So if you're looking for stuff like a Big top crowd atmosphere, mainly indistinct speech with generator in background from Nov '1979..... they have !
Take a look : http://bbcsfx.acropolis.org.uk/