go.stillinbeta.com is a short-term URL shortener, ideal for transferring a long URL from one device (e.g. a phone) to another. An Android application allows the sharing of URLs from within other applications. The backend is written in Django, and the web frontend uses Bootstrap because so does everyone else.
Friendheat is a webapp that shows a heatmap of your Facebook friends. It uses the Google Maps API, the Facebook API, jQuery, and Tornado to cache geocoding requests.
I use this application to manage an inventory of my possessions. It's written in Ruby for Sinatra, and uses CouchDB for storage. HAML and JQuery are used for rendering views.
Yes, this is a little meta. This site was developed using Django. I know it isn't the most attractive website you've ever seen. Cut me some slack, the designer hat doesn't fit me very well.
UTORdroid is an Android app for logging in to the University of Toronto campus wireless network. It uses the TagSoup library, which implements the SAX api. There's now a 802.1x-based network, so it's pretty much useless.