I thought this was quite a cool idea. It is an Arduino wirelessly display letters rotating round. Although it is not smooth, going by some of the comments this can be arranged. This has also helped giving me ideas in what I should make when coming to the projects.
Rumble robots is such a cool idea and at some stage I would love to make my arduino into something similar to this. Check it out!
This youtube video is about overclocking an arduino, it is overclocked to 16 mhz and 32 mhz and is running the blink program. It is quite cool and you can clearly see the difference between them.
Here is another link to another arduiono project that would be cool to make. It is a midi interface program using the arduino. I think bringing music and the arduino together will be quite cool!