Richard Feynman OP-1 Audio Samples
I think Feynman's lectures and talks are a good source for some very cool audio samples. Feynman spoke with great clarity and enuniciation - these qualities make it easy to clip samples and integrate them in audio track. Download them from op1.fun : Link and if you'd like to download it directly as a .zip file: Link.
Not to mention the uber geek factor of the content of what he says.
All samples are free to use, if you'd like you can credit to: hypersubatomic. Enjoy!