Old radios from the 1980s are cheap and easy to find. They also still sound fantastic, but the problem is that most aren't really compatible with modern hardware. DIYer Michaël Duerinckx decided the best way to update an old radio was to add in a line-in so he could choose his own audio source.
The basic process here was a bit of trial and error until Duerinckx found a place he could wire in the new socket. Then, after a little bit of solder, the line-in was up and running. He added in a few modifications to the case so it looked flush with the rest, and now that lovely vintage stereo is alive again as a speaker. It's not exactly the easiest project in the world, but the end result is a set of speakers that only you will have. Head over to Duerinxkx's site for the full guide.
Hacking a line-in socket into an 80s radio and cassette player [Michaël Duerinckx via Hack a Day]