MDX: Filter on Dates Before Today

A few days ago somebody came to me with a case where he had a cube with a customer dimension. The customer dimension had two attributes called Start Date and End Date. He wanted to filter the customer dimension where the Start Date is <= today and the End Date is >= today. Both the Start Date and End Date attributes are in the form of [YYYYMMDD], an integer, which is an FK to the key of the date dimension.