Mestat gathers and displays various stats from your Google App Engine's memcache instances. It also includes some minor utilities that are missing from the App Engine live admin dashborard, like flushing the whole memcache for an app.
Trackon runs on Google App Engine and monitors the features, health, and status of open BitTorrent trackers.
A drag and drop utility to convert PDFs into text via OCR.
A flexible I/O tester/benchmarker.