We have a cable to get sound piped from our stereo (record player etc, input) to our computer for capture as .wav files. This way we can burn music CDs from our old collection on various media. Marion found some freeware to reduce the WAVs to MP3s.
I found to my dismay that our newer amplifier had no provision for microphone input. After rejecting all the fairly expensive commercial microphone preamps, Hazel and I got to make one ourselves as a science project. This wasn't really all that hard. We bought a cheap old stereo amp from Goodwill that had this feature, took it apart to see how it worked, and put it back together in it's old box (cut down somewhat for aesthetic & space reasons).
Hazel's Home Recordings (size, duration {min:sec} & title):