I've spoken with many people who want to learn to play an instrument.  Naturally, my advice is to learn how to play harmonica, the friendliest of all instruments. You can put this little baby in your pocket, take it out whenever the urge hits you and bang- instant music. Even if you barely know how to play, the humble harmonica is very obliging- put your mouth anywhere and blow, and a major chord comes out. Do the same thing on the inhale, and a seventh chord, a ninth chord, or a minor chord will come out. It’s the only wind instrument that can play chords- not to mention rhythms, and of course, single notes. Or combinations of chords, rhythms and single notes, and even counterpoint! There is so much music hiding inside this little instrument! As you learn harmonica, it will delight you, impress your friends, fill you with a sense of wonder, even joy, at the hidden treasures that you gradually unlock as you play more and more.