a CD4093 integrated circuit (Digi-Key stock #296-2068-5-ND), aka a Quad NAND Schmitt Trigger
a CD4040 integrated circuit (Digi-Key stock #296-2048-5-ND), aka a 12-bit Binary/Ripple Counter[11]
a 0.1 μF ceramic disk capacitor (These are usually marked 104.)
a 10 μF electrolytic capacitor
a 100k ohm variable resistor, preferably linear tapers
three 10k ohm variable resistors, preferably audio tapers, not linear tapers (See Audio Tapers vs. Linear Tapers in Building It for details.)
three 10k ohm resistors (coded with brown-black-orange stripes)
a 1/4″ mono phone jack (guitar jack)
a length of coat hanger or similar stiff wire
a playing card (or any fancy cardboard or thin plastic)
a cylindrical control knob that fits over the shaft of your 100k ohm variable resistor, such as RadioShack part #274-403
three more control knobs, either the same as above or something more stylish, such as RadioShack part #274-415
a 9-volt battery clip
a 9-volt battery
a momentary push-button switch, such as a doorbell switch
a cigar box or similar enclosure
24-gauge insulated hook-up wire (Stranded is better, and you might want to get several colors to help you keep connections straight.)
22- or 24-gauge bare bus wire
a small printed circuit board, such as RadioShack #276-148
double-sided foam tape
(optional, but strongly recommended) a 14-pin IC socket and a 16-pin IC socket (You can substitute an 18- or 20-pin socket for the 16-pin one if it is easier to find; any of them will work fine.)
[11] There are plenty of CD4093 and CD4040s out there that will work fine; these are the cheapest at the time of writing. If you end up ordering something else, just be sure that it has a DIP layout and can tolerate being powered by 9 volts (most ICs in this family are fine with 5–20 volts).