LED Light Board (Light Bright?)

Hello Everyone -

I'm sure this is a dumb question and the solution is probably very easy and I'll be ridiculed relentlessly for asking it but...

Basically I want to create an LED light board about 12 inches by 20 inches rectangular. It's very simple, I just want to have three different colored LEDs on the board and create an image. Nothing crazy. Like Light Bright. It would be cool if it could maybe become a monitor itself, different LEDs lighting up to create whatever image according to a program, but this isn't entirely necessary.

Does my description make sense?

I would just like a jump start on how I could get this going. Any ideas? Does this even require an Arduino? : /

Basically I want to create an LED light board about 12 inches by 20 inches rectangular.

If you space the LEDs 6" apart in one direction, and 10" apart in the other direction, that's only 9 LEDs total. Piece of cake.

If you want them closer than that, you might mention that.