I take the kiddo to the library fairly often, and in the kid area they have low tables with some paper and blank bookmarks. Unfortunately (but understandably), the art supplies on offer are big stubby crayons and some mediocre, kid safe markers.
I've made the best of the available art supplies, but I recently started to bring a ballpoint pen with me. I'm also trying to have some prepared ideas to try for the odd format.
Just some fun doodles.