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.

I wont fuck off. This is a general request, without specifications like 'it has to be a game', 'it has to do x', as most competitions have. The size limit is a limitation of the OS.

Now, in lack of imagination, what could be an interesting problem to solve?