I used to trigger NMI by shorting the first two pins on an empty ISA slot with a screwdriver (conveniently NMI and GND); stopped when the screwdriver slipped on

I used to trigger NMI by shorting the first two pins on an empty ISA slot with a screwdriver (conveniently NMI and GND); stopped when the screwdriver slipped once. Thankfully nothing died on that day, but the cascade of sparks convinced me to install a proper button. ;)