I just thought I'd throw this one up here in case anyone ever has to do something like this on their SFDC Org. 

We need to track revenue on a custom object by Fiscal Period, but the users don't like having to pick and chose a specific date using the Calendar Pop-Up on the standard Date field. So I created a simple picklist with the Fiscal Periods that they want to break out revenue by for Reports, and created a custom Formula(Date) field

This allows us to run reports on Revenue Projections over a period of time using the Formula(Date) field, while the users get to have their simple picklist.

* There are 2 Record Types for the custom object, that's why  one set of picklist values is for FY and another set is for FQ

CASE( Forecast_Period__c ,
"FY 2009", DATE(2009,1,1),
"FY 2010", DATE(2010,1,1),
"FY 2011", DATE(2011,1,1),
"FY 2009-Q1", DATE(2009,1,1),
"FY 2009-Q2", DATE(2009,4,1),
"FY 2009-Q3", DATE(2009,7,1),
"FY 2009-Q4", DATE(2009,10,1),
"FY 2010-Q1", DATE(2010,1,1),
"FY 2010-Q2", DATE(2010,4,1),
"FY 2010-Q3", DATE(2010,7,1),
"FY 2010-Q4", DATE(2010,10,1),
"FY 2011-Q1", DATE(2011,1,1),
"FY 2011-Q2", DATE(2011,4,1),
"FY 2011-Q3", DATE(2011,7,1),
"FY 2011-Q4", DATE(2011,10,1),
NULL)