Need idea for C program on low-end device!

I'm looking for ideas for something to make for this embedded device. It has a 128x64px black/white LCD for output and keys for input.
Nao, I can program this is C, and I need some new, fresh idea. It has to fit in around 32k of RAM.

Lisp can work on this.  I presume it's 32k of free RAM alongside some sort of [BI]OS to lighten the programmer's burden.  It's worked on machines smaller than that.