I have one of these: https://pic8.co/sh/byQBvc.png on my bench. With the addition of a 1N34A, or any of the Soviet-era Ge diodes, you have a radio. It's only good for strong local stations, but we have plenty of those. It's great for dumping audio into a set where you're not sure how well the inputs are isolated - no parts to burn out if there's B+ on the input. Other than that, it's just kind of cool to sit there with an earpiece and a coil of wire and listen to the radio with no power input at all.