I moved into a different house this year, and noticed immediately that the front concrete fence looked like a bunch of pixels. So of course, I had to turn it into a giant display for Christmas.
I used a Diecimila and 30 ShiftBrite modules. Wrote some code to cycle a few animations, nothing very complex. I might clean it up and post it here for completeness.
Anyway, the video is available below. I'm pretty happy with the results...and seeing that there are a few more rows of pixels possible. 
Where be the video below? 
I'd like to see it.
It's embedded into the post. You don't see videos embedded in the Arduino forums? Lots of people are using them....
Anyway, I've edited the post with a direct link.
Thanks... I don't see anything embedded... I'll check with Internet Explorer (I'm running Firefox)...
EDIT: Ahh. It works in Internet Explorer but not in Firefox...
Thanks!
I'm using Firefox too. Seems to work...do you have Flash installed for Firefox? Maybe it's an Adblock or Noscript thing?
I see it, Im using FF as well.
Its very cool = )
It's very cool.
Yes indeed. Thanks for sharing!
Mikal
The ShiftBrite is an i2c client, right? How do you assign or learn the individual nodes addresses?
It's addressed as a giant shift register, the devices know where they are because of their physical location in the chain. You don't have to program addresses into the devices.
Ah, that explains your lighting patterns.
I'm actually writing the entire array at every update. I could reverse the direction, randomly turn on individual pixels, etc.
Does your program know that you've hooked up 30, then? You have to bang out N shifts for N lights, wait, decide what to draw next, repeat. They take 10bits * RGB per light, right? You don't see any flicker if you're "shifting" a bright pixel into place?
The program needs to know how many devices are in a chain. You don't see flicker during the shifting process because there's a latch line that you use to activate the new values once you've shifted the whole chain. Flicker can happen, but that's communication problems if you have heavy electrical noise sources like Tesla coils, or your power supply can't handle the sudden power draws.