I've integrated a php based AIM script into my Drupal site http://www.zacker.org . I'm using it for a few different things. Most notably I have built the ability to post and reply to comments / threads on my site via AIM.
I believe this site is running Drupal 4.1, but it deserves recognition on this site.
Tracking Leaves: Online Journaling- a writer's resource about 'your experience' as a naturalist. Nature writing, tracking, and anything about the outdoors. Starts first with your writing and accompanies it with the critique and interaction of other fellow nature enthusiasts.
Things that I took notice of were ...
The nice use of taxonomy sorted by vid and tid, as well as the dhtml over-view page under [Topic Tree] with vid/tid sorting there as well.
Dynamic javascript search box for all nodes on the site, Search results have title and teaser extracted as well as basic highlighting, a new quiz module was implemented
I got my site pretty much up & running! I had my content already, just had to transfer it, and I still have some left to do. http://knowislam.info/drupal/?q=
I am on the default theme, but I really like it! I'm not sure I need to change it at all.
Well, I don't think this belongs in any showcase, but I've been playing with Drupal for a little while and have been looking forward to giving it a test.
celcode.com is basically an online scrapbook where I'll post misc. articles, reviews, and php scripts. Right now it just has one lonely drupal article and link2this - a small php class to help webmasters develop backlinks (the old fashioned way).