This article is from the Baby Proofing FAQ, by Sandra Smith, firstname.lastname@example.org with numerous contributions by others.
From: Judy Boxer, Bitstream, Inc., Cambridge, MA
I strongly recommend that anyone with children (and without!) install Ground
Fault Circuit Interrupter (GFCI) plugs at all outlets in the kitchen, bathroom,
and outdoors! They will stop the flow of electricity if an appliance touches
water, and prevent electrocution. They are easy to install (they come with
directions - but don't do it if you don't know how to turn off the main power
switch). If you can't do it yourself, it's well worth the money to have a
handyman or electrician do it for you. These are the plugs you see in new
homes and hotels that have the test/reset button in the middle. They only cost
a few dollars and could save your child's life!
Also, if you already have these type of plugs, make sure you test them monthly.
It's easy: plug something in (nightlight, hair dryer) and press the test button.
It should stop working. Then press reset - it should start working again.