You can build some of the parts that make up Erica. Making something flash lights, move, squeek is a fun and educational project!
Although we used a fairly complex LED system to add so many – it is easy to try similar things with a berryclip.
You can try a webcam easily – see our notes
servos are fairly easy to use too – there is a nice guide from Adafruit here
Make a small display:
Not quite like Erica’s side-screens but these little screens are very easy to use – try making your own alarm clock for example