Without any electrical engineering background, my colleague Bo Bleckel and I attempted to connect a liquid crystal display to the arduino. However, we couldn't find a way of connecting the variable resistor to the system.
We even attempted to connect the arduino board to an M-Audio active speaker (should have used a passive one), again, without success. hannah, meanwhile, is having a lot of fun with her experiments, using example sheets. Down here is an example of the experiment she did with 8 blinking lights.
Eventually, we had the crazy idea of connecting a servo to the board. We followed the tutorial at http://arduino.cc/en/uploads/Tutorial/sweep
and it worked! The servo was moving.
This is the schematic
Here's the video of our system:
After the initial fails, our hearts were filled with this achievement. We will keep trying these entertaining experiments and get more familiar with circuits. More soon!