What are the little black pads on the bottom called?

Are you talking about the 4 little feet?

https://support.apple.com/kb/HT5236

http://www.amazon.com/Bottom-Feet-Replacement-Set-Macbook/dp/B0055U863S

https://encrypted.google.com/search?q=%22macbook+pro%22+feet&ie=utf-8&oe=utf-8&a q=t&rls=org.mozilla:en-US:official&client=firefox-a

As Shootist007 says "feet".

I have 2 macbooks and I installed new "feet' beside the original ones to give me an extra 1/4 inch in height on my macbooks for better air circulation in the bottom when I'm using it on my desk.

You can buy those "feet" from you local electronics or computer store for around $.99 to $2.99 for a pack of 4, depending where you shop.

Feet.

feet. Try checking at the Apple stores. They might have 'em in stock. I just got some for my daughter's 7 year old G4 iBook that she uses as a backup.