I found these to be very yummy.
Slice skinless avocado into thin strips
Line on a piece of foil
Season to taste (I used salt, pepper, and onion powder)
Bake at 375 for 10-15 minutes
Bake for another 20-25 mins or until outside is slightly browned and somewhat crispy.
More specific instructions found here:
Thread: Avocado Fries!