Mozilla has a publicly accessible ElasticSearch cluster filled with all Bugzilla's public bugs [read more]. This cluster is updated every 10 minutes, so it is not too far behind.
This is a simple, and silly, page to demonstrate the text searching capabilities of ElasticSearch.
###Nov 9th, 2014###
Over the past year, my professional effort has gone into using this cluster, and others, as a data warehouse; and ElasticSearch has proven to be very performant for this task. But, I have never had the opportunity to use ElasticSearch for what it was designed for - Searching documents!
This weekend I made a silly static page to demonstrate how the cluster can be used.