Question : Date Range Parameter - Last 8 weeks

I have a matrix report where I will have a start and end date parameter.  I need the End Date parameter to go back for the last eight weeks.  

So when the query runs it will automatically start on todays date and go back 8 weeks.

Answer : Date Range Parameter - Last 8 weeks

To do this in the report as opposed to sql server, select non-queried in the "Default Value" section and use one of these as the expression.  
To subtract 2 months (approx 8 weeks)
=CDate(Date.Today.AddMonths(-2))
To subtract 56 days (8 weeks x 7 days)
=CDate(Date.Today.AddDays(-56))