As the Views and Views Calc modules rely on the database to perform aggregation, you only have limited options at your disposal. As the great Merlin himself said: "You can't aggregate a PHP expression in the database. :/ ". That's where Views Aggregator Plus comes in. In addition to what Views and Views Calc do, this module: enumerates group members produces tallies, i.e. textual histograms aggregates on Views PHP code-snippet evalutations can filter out result rows on regexp patterns gives you sorting on Views' Math expressions can process Webform submissions lets you add your own custom aggregation functions ... and it puts summary statistics at the bottom of your aggregated table as well!

Remove strange items.
Place contrib projects to contrib folders.