So I built a real Humidifier intended for a much larger space.
Here is what you will need to build your own Evaporative self regulating Humidifier on the cheap.
Step 1: What you will need
A few super thick sponges
A small fan with switch (very quiet one from radio shack)
A tupperware plastic square bowl that is about the same size as the open part of the water dish
4 screws or bolts/nuts
Step 2: Cutting holes
Next screw or bolt the fan to the bottom of the bowl (see pic 1).
Step 3: Install The Fan
Now cut the sponge so that one piece fits in each of the four sides of the bowl (see pic 2) and covers only half of the openings on the plastic bowl so that the air can escape(see pic 3), and place it all in the auto pet water dish (see pic 1).
Step 4: Fin
I got this Idea from the HowStuffWorks.com its a perfect example of a evaporative humidifier.
If the link works you can view it here--> http://home.howstuffworks.com/humidifier3.htm
Enjoy the wet air