Etsy store iamhome sells handmade skulls covered with chalkboard paint so you can write notes to yourself on somebody’s noggin. In addition to modern human skulls, they also have Ardipithecus, Australopithecus, and Homo erectus models.
Their skulls are all handmade, which means no obvious seams and a nice smooth exterior for writing. The price really isn’t bad; a DIY version might be a little cheaper but not immensely: A fourth-quality skull from Skeleton Store is $18 and the paint would run around $10, plus you might need primer which is another $8. If you were making a bunch as gifts the DIY route might be a better deal, but as a one-off buying a ready-made one sounds a whole lot easier.
But! The chalkboard paint can be used to make a lot of other interesting objects write-on-able (that probably isn’t a word but it totally should be). For instance:
…plus anything else you’d like to give a creative makeover. Many of these, presented along with a box of colored chalk, would make a unique and inexpensive hostess gift as well.
Update: The fabulous Cookie pointed me to these instructions for making your own chalkboard paint, so the sky’s the limit in terms of available colors. Thanks, Cookie!