Here is an idea I came up with a while ago, which has seen some interest and further development around ye olde internete (Ie: HERE, HERE, and HERE). I never got around to posting about it here... until now.
It is a 64 step gate on/off pattern looper, based on the CMOS 4031 64 stage shift register. What is special about this design is you can manually "tap" your rhythmic sequence into the sequencer, unlike most DIY gate pattern sequencers, where you must program with toggle or other switches on each step.
Basically, the 4031 can record 64 steps of on/off information, and then spit that information out 64 clock steps after it is recorded. By looping the output back into the input, you can temporarily store 64 steps of on/off. Above it is x 2 shown gating two 4093 NAND oscillators.
It has a clock input, data input (which here is just a switch entering + DC voltage when pressed), and a loop, which has a NC switch, which when pressed, breaks the return of data, therefore clearing the loop.
Here is the schem of the basic idea.
And the grand finale - tap looper synced with the sparklebox/dazzlemachine.