Live site: http://albertkawmi.github.io/manyanalytics
Google provdes the handy [Google Analytics Query Explorer] (http://ga-dev-tools.appspot.com/explorer/) which is great for building all kinds of queries for Google Analytics. It even lets you select which of your analytics views (or properties) to run the query on. For many agencies or developers managing multiple sites, it is still a chore to run that same query on mutiple sites.
From personal experience, the main application I had for this is for getting lots of data tables into CSV format so that I could do further analysis, processing and visualisation outside of GA's own tools.
Twitter [@AlbertKawmi] (http://twitter.com/albertkawmi)