I'm listening right now to "Central Park in the Dark" by Charles Ives. And while he may not have been a multitasker in the purest sense, I love Ives because he was phenomenally successful in his music (even though much of it was never performed while he was alive) and in his day job as — of all things — an insurance agent. (In fact, I understand that Ives' work in estate planning is taught to this day.) Nice to see the analytical and artistical (a neologism in the spirit of Ogden Nash) coexisting so nicely. I've always admired his music so much because he was just too enthusiastic to be restricted by things like harmony and time signatures — a joyful, exuberant cacophony. (See, especially, the "orchestral raspberry" at the bombastic end of his Symphony No. 2. You can see and hear Leonard Bernstein conducting this piece on YouTube right here. The fun begins at 11:30 (where the brass come in) and peaks at the very end, at 12:38. Whee!)
And, while we're at it, it looks like Ives was also an accomplished athlete, having been the team captain and pitcher for the Hopkins Grammar School baseball team:
Way to go, Charles!