http://hackaday.com/2013/08/07/a-cold-cathode-audio-visualizer/
Any idea how he's making it rise from bottom to top like that? in the ccfls? he's using them as level indicators which is pretty cool but how he gets the mosfets to do that?..
A MOSFET is far more flexible than just an on-oiff switch. In between the "off" and "saturated" (i.e., "on") states there is a region where the MOSFET acts like a variable resistor where the resistance between the drain and source is proportional to the voltage between the gate and the source.
Vary the voltage into the gate (with filtered PWM say) so it is between the off and saturated states and you have a voltage controlled variable resistance which you can use to change voltages and currents at will.