Cosmonaut Komarov's final transmission
Alleged lost cosmonaut recording
The Max Headroom Incident
And while there's no recording of it (to my knowledge), when GAF was staying up listening to amateur repeater, and the crazy lady interrupted yelling "Bad bird!" over and over spliced with screaming... That was pretty creepy.
Also, a while back I heard an alleged 911 call of a woman who claimed she'd sighted a man outside her door or something. Then while on the phone with the operator she screams, and then there's silence, followed by her whining "Let me breathe. Please! Let me breathe." I don't know if it was real or not, but it scared the fuck out of me. I'm not even going to look for it, I found it so disturbing. If it was an act, I applaud them. They did a great job.