Dynamic Current Date Function When Creating Views

Hi.  A feature that I have been wanting for a really long time is the ability to build a view that can identify records that are On or before the current date, say "Contract Renewal Date".

Right now you can do that by hard coding a specific date such as Contract Renewal Date on or before"9/22/2016" but I want to be able to do this off a dynamic date.  If there were a Today function that would work and if I could say something like I want to identify all Contacts that have an Contract Renewal Date on or before "Today + 5" that would be perfect. 

Any ideas on how I might be able to do this in view?

Thanks.

Rick Bellefond
RB Data Services