You can find some "brainy" shirts at Threadless.com, including Bird Brain and Connect It:
Uncommon Goods features a number of items for the psychoanalyst in you. Here are Freudian Slippers, psychoanalyst finger puppets and the always popular Tickle Me Freud, as well as the Rorschock party game and Mind Games (A Box of Psychological Play).
For more unique psych-related gifts check out the people who make lots of handmade stuff on Etsy. For example, by plugging in the keyword "psychology" I was able to find among other things dopamine jewelry and some really cool buttons. Keep in mind these are in limited quantities but they may be far more unique than the other options above.
So what about you -- where do you get your favorite psych-related gifts? Or what's on your wish list this year? Please share your ideas in the comments below!