Hotel Chaching has the latest Hollywood movies and network TV shows on-demand on your guest room TV, and it will cost you--$14.99 to rent one movie. We can do better.
You probably already have a Netflix plan. (For about ten bucks a month, you can stream movies and TV shows to your laptop computer.) Amazon.com also streams movies and TV shows, many of which are free if you have a Prime account. And Hulu.com is a great place to catch up on the latest prime-time network TV shows, free. Of course, you can watch on your computer, but with a little inexpensive tech we can improve the experience.
Many hotels have media docks that let you plug your equipment right into the TV without having to dig around behind the furniture. You'll need to bring an extra cable. If your laptop has an HDMI cable output, you lucky devil, this step is easy. One cheap HDMI cable [compare prices] is all you need to connect your laptop with the hotel's media dock or straight into the TV.
DVI is another common laptop computer-to-TV interface, and will give you a pretty good picture. If you have a DVI output on your laptop, a DVI-to-HDMI adapter cable [compare prices] will do the trick in most hotel rooms. You'll need to add an audio cable; see below.
More typically, a laptop will have a 15-pin VGA jack that's used to connect it to an external monitor. You'll need a cable that converts it to an input the TV can use, like an S-video cable. Luckily these cables are common and cost a couple of bucks [compare prices]. You'll also need an audio cable that connects the computer's speaker or headphone jack to the audio-in of the hotel's TV [compare prices]. These are also cheap and readily available.
(Confused? How Stuff Works has an article describing this in more detail. Once you get the right cables, the rest is easy.)
Not traveling with a laptop? I've been known to pack up my old-school Apple TV [compare prices] (it's only about the size of my outspread palm) and hook it straight into the TV with an HDMI cable. It takes about thirty seconds and give me access to my entire home library of movies, TV shows and iTunes songs. Beware, though; the new version of Apple TV has no hard drive; it only streams content, which means you'll have to have an Internet connection to make it work.
Congratulations! You've invested less than $5 in cables and saved $15 or more every night you stay in a hotel. And you're very entertained. But don't stop there...