So about 2 years ago, the guy who built the CRM which I work on at work decided that storing dates in the format mm/dd/yyyy as a tinytext was appropriate for one of the tables. So today, after making a bunch of changes to the file that processes this data to format it correctly, I had to change the db data to match the new format. Thus, the magical str_to_date sql statement comes into play. Here it is for future reference:
UPDATE table
SET timestamp=str_to_date( `timestamp` , '%m/%d/%Y %h:%i:%s' )
This takes the current data (mm/dd/yyyy) and converts it to the proper data type for a DATETIME field (YYYY-MM-DD HH:MM:SS).
PS- No, I don't know why a field named "timestamp" was storing the date, and not the time. If I did, I'd likely throttle the former developer...