We had a customer who had built an OLAP cube over a fact with 10 years worth of history. Whenever the cube was browsed though in Business Objects or Excel it would show dates going back to 1950 - which are all the dates held in the date dimension. This meant that the user would have to scroll through years of empty cells to get to 2000 when the data actually started.
The problem was caused by a calculated member that returned a 0 when the calculation returned an empty value. This caused the cube browsers to think that there was data back to 1950. So rewriting the calculated member to return an empty value when the calculation returned nothing caused everything to come right in the front end.