ExtJS 2.1 saw inclusion of the (at least in my world) popular user extension for AJAX filtering of data by grid columns. As useful as this is (provided you can abide by the GPL or paid licensing options), the filtering data is formatted as a PHP array, which is not terrifically useful for other languages. With a quick modification to the grid filtering class and a Django helper, the grid can send a JSON string that Django can use to directly apply filtering to a QuerySet. I've found that most clients love having the ability to peruse their data this way, and the amount of work to get everything set up is minimal. Even better, the code is minimal, reusable, and pretty straight-forward. I like that.