During the Splunk Conf they showed an spread sheet that had reports and whenever it was opened it would go back and query the information from Splunk to update the information on the fly.
What is that called? Is there any documentation for it?
i believe what you're talking about is called lookups:
typically, this feature is used to bring in information from said spreadsheet and add it to your search results, but you can also use the 'outputlookup' command to write results from a search to a file on your filesystem:
if you ran a scheduled saved search that included an outputlookup command, you could achieve the situation you describe, although it won't update the spreadsheet automatically just by opening it.
this module might also achieve some of your goals;
but i'm in retrospect (thanks #splunk IRC!) thinking you meant this: