My father is part of a military band of sorts, and has been playing various instruments (B-flat trumpet, tuba, all kinds of guitars) as long as I can remember, and it turns out my siblings and I also have a natural talent for music.
First off, not an instrument, but I've been singing since I started learning to talk. One of my siblings (or myself) kind of just start randomly singing and the others join in, and we can easily pick up different parts of a duet or spontaneously give each other solos (for example, we sing together for the whole song until a rap part comes up. Then they both drop off and let me fly through that xD). So yeah, that's fun.
As for actual instruments, I played clarinet for a couple of years, but I haven't been playing it at all recently. I should probably start re-learning it. I also have an electric keyboard that I never formally learned how to play, but I can still work out some simple melodies on that. Whenever I see a piano I HAVE to play the one song I know how to: Megalovania.
Two of my siblings are going to junior high this year, and I'm hoping one of them will join band! They can't play anything yet, but my bro has tried trumpet and my clarinet, and my sis wants to learn violin.