Whenever I am feeling uncreative, I check the blog of Sam Ricks, an illustrator who always has something zany to show the world. My favorite posts of his are when he just scans an entire page of his Moleskine sketchbook and presents it without context or comment. Here is a recent series.
Boecio, barber of Greece, part i.
It takes an active imagination to come up with these kinds of things. I suspect, however, that just putting a pencil point on paper feeds an inactive imagination.