For sure, activities that are intrinsically fun/challenging/engaging and that ultimately result in unexpected, tangible financial payouts are the best. In real

For sure, activities that are intrinsically fun/challenging/engaging and that ultimately result in unexpected, tangible financial payouts are the best. In reality, I find myself doing a lot of projects at my 9-5 where I need to be realistic and explicit about their expected value - especially when I need to be accountable to my boss who has business goals to meet, and who knows the approximate value of each hour of my time in the office. So it's nice to do things with no metrics or strings attached or bosses (besides myself) in my free time. Luckily I don't have to justify every activity at work...such as reading/commenting on HN :)