MOTM

To summarize (in increasing high frequency content order):

Red noise - very low frequency content, almost subaudio, akin to slow 
random.

Pink noise - equal energy per octave, sounds like low-Q wind (open 
your car windows at 70 mph)

White noise - equal energy per unit bandwidth, sounds higher pitched 
like steam.

Blue noise - energy increases with frequency, has the most high 
frequency content of all.

You can obtain practical audio approximations of these using white 
noise and highpass or lowpass filters, so the terms sound more exotic 
than they really are.

Moe