I'm always getting confused between the UK and US formats:
For UK format i.e. dd/mm/yyyy, the style parameter is 103
CONVERT (DATETIME, '18/12/2005 00:00:00', 103)
For US format i.e. mm/dd/yyyy, the style parameter is 101
CONVERT (DATETIME, '18/12/2005 00:00:00', 101)
And I really wish that people would give examples like '18/12/2005' where it's quite obvious which is the date and which is the month instead of the normal examples like '04/06/2005' where it could be either.