Cable Release: I highly recommend this. I have a wireless one, which I usually do not use because it requires line of sight, and a wired intervalometer like this one. It is invaluable to minimizing shake and when using bulb-mode (e.g., fireworks, long exposure shots). I tried Magic Lantern, but I prefer to use my wired intervalometer.
Well, just for the op's information: with magic lantern, you can release the shutter by the sound of snapping your finger near the camera - works for me. And of course ml has real timelapse, bulb ramping and advanced scripting, you could write a script to release the shutter after any wait time or in any interval you want.