The NodeCarousel module helps bring the jCarousel plugin for jQuery into easy use for drupalers who want to display their nodes with the ability to scroll through them side-to-side or otherwise shift through the nodes with ajax.

The DME module lets you define markup for your users to use in their posts, and declare exactly what that markup should be replaced with. You don't have to do any mucking around with regular expressions to find the tags you've defined - the DME does that for you, and passes to your custom code the name of the tag, the arguments entered and any and all text enclosed by the tag. On the PopSci website, for example, we declared a tag that lets them decide where images appear in the flow of their articles.

Both of these modules use SimpleTest testing - unfortunately, the NodeCarousel testing still assumes database items, but the DME tests can be run yourself if you like, as the DME is independent from the database.

Give them a try! I've got some definite plans for the NodeCarousel, both in expanding what it can do, and with updating it to the new Drupal 6.