There are seasonal contests where you create your own photo (referred to as an armatar) relating to the event - so when Halloween comes around you could create a Halloween-related armatar in the sticky in the Art Music and Writing forum. So you can't exactly personalise it too much, but the armatar would still have been made by you.
Otherwise, not as far as I'm aware. If you want to change your armatar go to Control Panel under your account name and then click on Armatar in the top right(?) corner.
