Maxim shows how to build a LED brightness controller with 64 level of control using push buttons. The design incorporates a current regulator that is driven by a 64 tap digital potentiometer. The buttons increment and decrement the tap.
Via Electronics-Lab.
5 V output is handy. Cool how the chip provides current for the LED string and regulated voltage for the control circuits, all from the single power input. Unfortunately, the 5 V output is only 4 mA, which seems small compared to the 350 mA current for the LED string, but I suppose it makes sense.