The only things I've found so far are a cart method (which ceased working in 1.6), a dispenser method (utilizing the decay on dropped items, but this requires occasional feeding), and a binary counter (which won't work for a single input but rather a fluctuating one).
I want to have a circuit that when I apply an input signal, the output signal doesn't change for 2 to 5 minutes. When the input turns off, I again want a 2 to 5 minute delay.
I could accomplish this with (roughly) 240 to 600 redstone repeaters, but this is far in excess of being useful.
The only method I can think of, but would require a XOR gate (on the button-input and final output) to start and stop a clock attached to a binary counter. While I can make room for a device of this size, I was hoping for something simpler.