[NCARC] Need help debugging electronics project

[Ed Gage]

I've developed a relay control based on the Basic Stamp, and need help
debugging it.  There is either some transient noise produced by the relays,
or some sort of surge.  I've put a diode across the coils which helped
control it somewhat, but I'm at a loss as to what is happening.

On powerup, 8 relays are charged with 12V, to drive 120V that runs 8
incandescent light bulbs.  The same 12V powers the Basic Stamp, which
controls the relays based on input from 8 buttons.  The project is a
"lock-out" game, where first press gets solid lamp, 2nd gets fastblink, and
3rd gets slowblink.  Additional buttons get no blink.  A reset to the Basic
Stamp resets the lock-outs.

What happens is when the second and third buttons are pressed, after
several blinks, sometimes the system resets itself, without user input.
 I'm at a loss as to why this happens.  However, I discovered I could
prevent the reset by touching one of the two leads for the relay.  My
assumption was that I was suppressing some sort of electric surge that was
happening with my body acting as a conduit to ground.

Perhaps somebody could elaborate on why this phenomenon occurs?

Anyone willing to come help would be treated to a nice dinner.

--Ed Gage, NØTVQ