Forgot the plug? No converter? Have a smartphone? Ahem, just plug it into the TV.
Who knows how many times I've done a very thorough job of packing everything... except my phone charger. Thanks to this Lifehacker tip there is no longer any need to go buy a new charger when you've forgotten it on the road. Chances are most hotel TVs (mainly smart TV's) have a USB port.
Regardless of the suggested use of your television's USB port, chances are it receives power. That means you can actually use it to charge USB devices, such as your smartphone or even a game controller.
This works for almost anything that has a USB port being powered by something else. Here's also a list of other uses for the unused ports in the back of TVs.