CamStudio is able to record all screen and audio activity on your computer and create industry-standard AVI video files and using its built-in SWF Producer can turn those AVIs into lean, mean, bandwidth-friendly Streaming Flash videos (SWFs)
You have total control over the output of your video: you can choose to use custom cursors, to record the whole screen or just a section of it and can reduce or increase the quality of the recording depending on if you want smaller videos (for emailing to people, for instance) or you can have "best quality" ones for burning onto CD/DVD.
A number of people have mentioned having trouble viewing SWF videos generated by CamStudio. It turns out there's a bug which means you can't see anything if you try watching them with Netscape or Firefox (Internet Explorer works fine).
This is great for middle school students or 9th -12th graders.

Audacity is popular open source multilingual audio editor and recorder software that is used to record and edit sounds. It is free and works on Windows, Mac OS X, GNU/Linux and other operating systems.
Audacity can be used to perform a number of audio editing and recording tasks such as making ringtones, mixing stereo tracks, transferring tapes and records to computer or CD, splitting recordings into separate tracks and more. The Audacity Wiki provides in depth tutorials on how to do these types of tasks in Audacity.

The biggest challenge is the recording in .aup format. You must have an encoder in order to transfer to a .mp3 file (which is necessary in order to use files for podcasts).
This is great for middle school students or 9th -12th graders.

Freemake Video Converter can do some basic video editing operations: cut unwanted video parts, join files, or rotate video. With Gold Pack release it also got the option to delete black bars. Still it has never pretended to be a fully-featured video editor; it's a video converter. This allows students to download videos from YouTube or their cellular phones for the use of an assignment.
The program's Help pages are very good. The tutorials come with a short video as well as images which are very easy to understand. There seem to be a lot of hidden gems in this converter as well, such as a few editing features for videos and the ability to add subtitles to your videos when you rip them from your DVDs. You can also convert photos and have plenty of conversion options.
This is great for middle school students or 9th -12th graders.