When I open my sketchbook and my muse spats in fear and runs from the room, I turn to font drawing for solace. I have many books of font exemplars so I simply pull one from the shelf, thumb through the pages, and pick a font to practice in my journal. (This book of circus alphabets from Dover is my all-time favorite; my copy is dog-eared and well-loved.
This isn't "high" art by any means but the quiet time spent doodling and coloring letters helps pass the time until my muse decides to join me in the studio for more complex work. In fact, this type of page can often coax the muse out of her hiding place like a tasty tuna treat can lure a shy kitty out from under the couch. One minute, there's this hissing, frightened creature and then, with a little love and patience, that kitty is twirling herself about your legs, purring and mewing for more. My muse is very much like a temperamental cat and I need only observe my actual cats to remember how to make friends with my muse and put her at ease.