I know there are probably better forums dedicated to this sort of stuff, but I wonder if anyone can give me a little direction before I start searching with little idea of what I'm doing.

Basically I wanna add a night sky to a childs bedroom, getting a false ceiling fitted wont be difficult as the rooms here are designed to have that done anyway and we can pay some hombre a few quid to do it.

I wanna have say 50 LEDs that I can control to create a nice effect, not flashing like a christmas tree but pulsing with 3 or 4 independent sets of lights, so it looks less computerized.

Anyone have some ideas? Not afraid of making my own circuits but I wanna avoid too much expense with arduino and such devices.