You can do this by first creating a float parameter (if desired, place a range of numbers, create a list or use all). Then, create a calculated field from the parameter similar to the following:
if [Order Date]>=today() and [Order Date]<=dateadd('day', [Date Range], today()) then [Order Date] end
For this example, Order Date is your date field and Date Range is the parameter. Then, right click on the parameter in the data box and select Show Parameter control. This calculation will allow the user to see the number of days from whatever today is.
Place the calculation on the filter shelf. Choose the Select from List option, click None. Then, check the Exclude box and check Null.
Hope this helps!