The word "smartest" in the title misses the mark slightly in a way that exposes the idea to too-easy dismissal. The way people commonly use "smart" (high IQ, basically) isn't super-correlated with what Chris is talking about. Many high-IQ people are too locked-in to Achievement to bother with disinterested play. You can redefine "smartest" to mean "those who turn out to have been most ahead of their time", but that's circular and doesn't help identify the quality.

The body of the post uses the word "hobby", though, and that's much better. Your hobby is the thing you do because you want to, whether or not anything comes of it and whether or not anyone thinks it's valuable. Hobbies are marginal, not one's main or proper thing (Woz was an engineer at HP). And they're often wild or eccentric. The main reason we wouldn't normally use the word "hobby" for important creative activity—that it seems too trivial—is actually a point in its favour. Incidentally, there's an earlier usage of the word "hobby" that was closer to what we now call "obsession" or "fixation". People would apologize for introducing their hobbies into polite conversation.

One must also insist on the fact that very often nothing does come of this quality. To imagine otherwise is to allow no room for randomness.