I thought it would be fun if YouTube had some videos of an e-meter in action. The most direct demonstration I found was this one. However, this is part 3 of a three parts series and you'll get a lot of bla bla before the actual action if you are first going through parts 1 and 2. This being said, the series is probably the best introduction to Scientology I saw to date.
Searching YouTube also reveals the fact that there is little to nothing to "counter" that CoS' demonstration.
The "best" is this demonstration of what a simpler machine does, but it's borderline idiotic, because it only shows that it registers values in certain conditions and that the values changes as you adjust the level - and the video then finishes by a pompous line stating "before you join a religious group or any group, check your facts", when in guise of fact it offered barely nothing and what it offered was irrelevant. Here is a good answer to the argument from Homer Wilson Smith
Xenu.tv offers a clip about the history of the e-meter, that may be interesting in another context but does little to demonstrate anything here, and Anonymous offers a static image series taken from Wikipedia - boring and a waste of the potential of videos.
For the rest we are gratified with the usual bad taste jokes of Anonymous and their irritating mocking laugh.
I didn't bother to go much further down the list.