That might have been a lead-up to:
SELECT DATEADD(DAY, (DATEDIFF(DAY, 0, CURRENT_TIMESTAMP)), 0)
You can use the CONVERT function with a style parameter to format the result.
You can also use CONVERT to remove the time part. Some people find that more intuitive, though it is slower.
In SQL 2008, we have the DATE data type - which might be what you were looking for?
Paul