I have been experimenting with blabberize and I believe for all subjects it has a lot of potential. In a fun way you can introduce a topic or aware students of and emphasize on a commonly made mistake. Another good thing about blabberize is that when you have created a video, it gives you the html code so you can instantly embed in on a website (you can also download as a vlc file on your desktop). Have a look at the following two examples I made in less than a minute each. Let me know what you think!