Electricity
The electrical current is 220 volts, 50 cycles alternating current (AC), so most North American appliances can't be used without a converter. Older wall outlets take continental-type plugs, with two round prongs, whereas newer buildings take plugs with three flat, angled prongs or two flat prongs set at a "V" angle.
Electricity is a hit-and-miss thing in Argentina. Brief power outages (and surges when the power comes back) are fairly regular, so it's a good idea to unplug your laptop when leaving your hotel for the day.