I hate when you finish a project, and have no idea what to work on next! I despise feeling so idle!

If by any chance you are one of the few devs that can sleep, my advice is that to keep a notebook always near you during sleep hours, that way when you wake up write inmediatly the idea or ideas that get stuck in your head. I use that method and check my notebook after finishing a large project, then the hard part is to decide wich one is worth. :D

my friend, you're never finished with a project!

Have you heard of a site called Reddit? Downtime is a pretty glorious thing in our profession, but if you are truly someone who prefers to be constantly busy I can see how that would be annoying.

I keep a notebook near my bed too.
But I don't even need to wake up to write down my notes. Sometimes I wake up and answers to my problems are written in my notebook.
I must have been sleepwalking again.