Have taken up a new habit this past week - before I start working on the day's to-do-list (inking/lettering comics, working on bigger paintings, etc.), I do a short warm-up.
It's all sketchy and unfinished or lacking a background, or just really simple, but it's good exercise either way.
This is what I've made over the last few days:
And I also did this - because this is what I've looked like for most of the day. Except I'm not sitting in a grey void:
Charlie Chaplin and the self-portrait are done in Sai, the other in Painter IX.