[HH] Controlling lots of LEDs with a microcontroller

[David Kramer]

I would like to make a mask with a rotating message on it.  I'm debating
two completely different designs; one mechanical and one electronic.
Full description of the project at

http://wiki.thekramers.net/Main/GitsMask

If I decide to go with the electronic solution, I would need a ring
roughly 9"-10" in diameter, with enough LEDs on it to scroll words,
meaning 120 or more LEDs, where about half of them may be on at any time.

It's been a while since I've done serious embedded work, but I'm pretty
sure I'm up to the software and the hardware side.  There must be
examples out there about scrolling words on a sign for pretty much every
appropriate platform, and this is just bending it into a circle.

That's a lot of ports, though.  Most microcontrollers only have 3 or 4
8-bit output, which wouldn't even do half the job.  I am ideologically
attracted to Arduino, but if a more appropriate platform is available, I
would probably use it.

Anyone have any suggestions?

Thanks.