The following Splunk query will return a summary of weekend activity for a given IIS hosted website.

sourcetype="iis" (date_wday=saturday OR date_wday=sunday) | stats count(JSESSIONID) as Value | eval Metric="Total Hits on Weekends" | append  | append | append  | fieldformat Value=tostring(Value,"commas") | fields - count, percent | fields Metric, Value