You may have seen this when I made this as a project, but now it's a product. The Defusable Clock kit lets you build your own dangerous looking device. Only the electronics are in the kit, not the scary-scary looking parts.
This is based on Arduino technology (powered by an ATmega328 with Arduino bootloader so you can hack it!). Kit is $32.95 in the nootropic design store.
Also see the full product description here.