I used to love watching animated stick figures fight. Perhaps you could animate a miniature pixel guy battle on a 256x256 square or smaller.
2) Try creating an underwater coral reef scene. The colors and animations are more difficult to create, great practice.
3) Remake ANY 70/80/90's music video in pixel animation! Tiny music videos would be rediculously adorable and unique. Maybe display maybe local talent, animate them as pixel dudes jamming perhaps.