Things I Make Calliope (playlist toolkit) Calliope is a research project to create an open source music recommendations engine. Join the discussion on the Beets.io forum. Tracker (search engine) I co-maintain the Tracker search engine within GNOME. See my blog articles about Tracker for more information. Twitter Without Infinite Scroll Firefox extension for users of Twitter.com who don’t like Infinite Scroll. Lesson Planalyzer A working prototype of a desktop app for searching and browsing an archive of lesson plans.