This is inspirationally depressing. Really makes you realize what a shit human being you are when everyone is doing so many interesting things -- on the side.
I barely have enough time to work, go to the gym, and socialize. I don't know how anyone has enough time to add side projects on top of that.
Easy. I have three children. If I didn't have children, I'd have 3 Nobel Prizes by now with all that extra free time :)
Do you have a hobby? Most of my side projects (and if you notice, a lot of the projects here too) stem from a hobby. It's not work if you have fun doing it, and if it's a side project then you can stop whenever it stops being fun.