I bought a new sketchbook recently and have been enjoying drawing during some downtime. I also bought a cheap, ink-brush pen from a local convenience store. It's usually used for Japanese calligraphy but I love the random lines it gives.
Work for clients is often more restrained and the lines are more consistent etc so it's nice to just let loose in a way and just draw. It's kind of therapeutic and its the thing I'm most excited to do when I wake up.