USB memory sticks & memory cards
USB memory sticks are very effective and cheap media storage devices. Memory cards can be found inside digital cameras, mobile phones and other equipment. They can be accessed by dedicated memory card readers or by connecting the device to the computer with a USB cable. Often USB memory sticks are recognised by a computer as a removable device and can be used like any other media: drag files to the appropriate folder in your computer, eject the device and you are ready to go.
However, one thing to keep in mind is that a memory stick formatted for Mac or Linux may not work properly on a Windows PC (or the other way around). The best format to use, that will work on Mac, Windows and Linux, is FAT32. But remember, using this format you can only have files that are a maximum of 4GB in size.
Some DVD players, projectors and TVs also have USB inputs on them, allowing you to directly play your videos.
Mobile phones
Many mobile phones can access content online, however they can also be used as storage device to share files with computers or other phones.
If your phone has bluetooth you can use it to transfer files to and from an enabled computer, or directly between mobile phones. USB cables can of course also be used to file transfer.
Smartphones which have a web browser will often be able to play back videos on the web, as well as through dedicated apps and from files sitting on the phone itself. Some smartphones, such as the iPhone, will only play back videos that are in a very specific format. Research the type of phones you wish to target, how you will get video onto them, and what formats they will accept.