The AsciiMathML filter http://mathcs.chapman.edu/~jipsen/math/index.php/ASCIIMathML/ASCIIMathMLMoodleFilter.html works fine with resources, forums, and glossaries, but does not function in at least the quiz, chat and message modules. The TeX filter does work with these modules. The modules in which Asciimath works output the following bits of HTML. Where Asciimath doesn't work, theresulting HTML lacks these inclusions:

<script type="text/javascript" src="[wwwroot]filter/asciimath/ASCIIMathML.js"></script>
<span id="processasciimathinmoodle" class="[wwwroot]/filter/asciimath/"></span>

where [wwwroot] is the leading URL path to these moodle server.

With chat, the filter does not function for reading live messages with the frames interface, but does function if the recipient uses the non-frames interface, and does function for reading previous chat session transcripts. Similarly for the message module, asciimath does not function for reading a "live" message, but does properly display in message history. I have gotten this to partially work with Quiz by roughly modifying the filter's PHP to output both of the above scripts.

I've tried this with 1.8.4 and 1.9.14.1, with generic filter options "filter all strings" and "filter all files" enabled and disabled, and latest AsciiMathML (9/2007). I hope this does not have much to do with quiz, chat, and message, but rather with how the filter identifies itself. Asciimathml has many advantages over the TeX filter, outweighing for my purposes the need to install MathPlayer.

To see if Asciimathml is working, add browser plugin http://www.dessci.com/en/products/mathplayer/ for IE or http://www.mozilla.org/projects/mathml/fonts/ for FF. Enter a calculator-style math expression enclosed in single backquotes like `sqrt(n-1)` into the HTMLArea editor just like regular text. If it fails to function when the formatted page displays, you'll see what you typed. If it works, you'll see standard math notation.