If you’ve forgotten the charger for your iDoodad, before you run out to purchase a new power plug, ask the front desk of your hotel if they have an extra power cord.
If I’m in between places, I try to let my cell phone/laptop batteries fill up until the last possible minute before unplugging. Who knows when you’ll get the next time to juice up. Even if I followed the ultimate packing guide, I sometimes leave my power cords behind in my rush to get out the door.
Lucky for you (though it kinda sucks for the guy who left it), cell phone chargers are the most often left behind items in a hotel room, so the front desk often have these chargers on hand. (I hope you have your power converter, though.) I always return the borrowed power cords back to the front desk – it’s a small way to pay it forward to the next power-less traveler.