ttyrec is a tiny terminal utility that does this on your terminal. It was released in 2000, it's one of those nice little gems one is glad to discover. It records and playbacks terminal sessions. The recorded files are in kb's. [1]

It's simple to use. 'ttyrec filename' starts recording, ctrl-c to stop recording. 'ttyplay filename' to playback.

Of course with asciinema.org, you get the benefit of an html player for the files, that you can link and playback on your own website.

[1]http://0xcc.net/ttyrec/index.html.en [2]http://manpages.ubuntu.com/manpages/maverick/man1/ttyrec.1.h...