Fleep (note that the popup won't launch in Opera... grr). A quirky and surprisingly engaging series of comics. From the site:
It's about a boy who wakes up in a telephone booth which has been mysteriously selaed in an envelope of concrete. Using only the contents of his pockets (two pens, a paperback novel, three coins and 20 ft of unwaxed dental floss) our hero must fashion and execute an escape plan before he runs out of oxygen.
Not for everyone, I'm sure.