Oh yeah, I had many of those. Push a button, out pops a compartment with your eraser. Push another button, and there's a pencil sharpener! The only thing I hated about them was that for the top part that held your pencils, there was a size limit...my pencils with cool toppers wouldn't fit. :x
Edit: I found a picture of a Hello Kitty one.

They just called it a "pop-out pencil case". I forgot that they were double-sided as well!