Reel-to-reel tape players are a thing of the past, but the fundamentals of reading simple magnetic tape don't change. A video created by Scribd engineer Evan Long apparently shows a 1940s reel-to-reel recording being played back with an iPod touch and Square mobile credit card reader. According to Long's site, he started with the reader and some old reels of tape. From there, he bent the magnetic reader apart to let the tape flow through it easily, set it between the reels, and plugged it into the iPod. Since the iPod's headphone jack can act as a microphone, Long then used custom-written audio recording software to capture and play back sound from the tape.
Long shows off his setup in the video below, but he says that the (very quiet) audio he's shown recording is actually dubbed over, since it was being played back after the fact. We can't vouch for the veracity of this, but theoretically it's fairly plausible. If real, this is a pretty interesting combination of new and old technology.