Electrical.

An old two-prong outlet.

Because they used metal conduit most of these are actually grounded and easily converted to three-prong. One of the first electrical modifications I did in this house was in Josh's bedroom; there were wires coming out of an outlet that had exposed [bare] connections! [I've subsequently used that wire for grounding my new receptacles; see below.]

Why three outlets on these old receptacles? I don't know that three cords could actually fit; maybe the older type. Surprisingly, though, these better fit our night lights than the newer receptacles.

New receptacle with nightlight barely fits coffee maker plug. Old three place receptacle was actually roomier. 

A new three-prong replacement outlet.

I've done seven of these so far. Most of of our electric devices have three-prong cords. The narrow slot is supposed to be the "hot" wire, but since the wires coming into the electrical box are generally the same color I sometimes mix up hot and neutral. The wiring to these outlets is all two-wire, with the metal conduit providing the ground. That means I had add a third wire to ground these plastic constructed receptacles back to the conduit.

New power conditioner and surge protection at the tv and blue ray player.

The power is so schitzy here that all devices should really be plugged into some sort of protection. This conditioner can constantly be heard clicking as the power fluctuates. So far haven't had any long unplanned power outages. Have had one planned power outage that lasted most of one day; some sort of maintenance work that affected the entire lake, twelve or more communities.