There's quite a bit of evidence out there that says when children learn music at an early age, they do better on education later in life. You've set some neural pathways early on that help with learning math, languages, etc. I took piano lessons as a kid, moved on to violin (for one year), then drums and vocals.
I always wanted to learn to play some sort of stringed instrument. My brother plays guitar and bass. My dad played a little guitar in his youth. And being able to play and sing at the same time sounds much better on a stringed instrument than on drums. You can accompany yourself when you play chords instead of beats.
So... I got a ukulele.
For a soprano uke, a case to carry it, and some basic learning materials I paid less than $80. If I manage to get good at it, I'll upgrade the uke.
But to get back to my main point, if learning an instrument at a young age helps the brain, what does learning an instrument at a (cough) slightly older age do for you? I'm about to find out, I guess. My current job has made me stupid. That's the only way I can describe it. It's a boring, mindless, repetitive job that requires little-to-no brainpower, and I can actually see the decline in mental ability over the past three years. To be frank, that both scares me and pisses me off. That's part of the reason I'm taking college classes again, and between those classes and picking up an instrument and learning not only how to play it but chord progression and musical theory should help me recover what I've lost.
Besides, it'll help break the ice at parties, don't you think?