How can I overcome "datetime.datetime not JSON serializable"?

I have a basic dict as follows:

sample = {}
sample['title'] = "String"
sample['somedate'] = somedatetimehere

When I try to do jsonify(sample) I get:

TypeError: datetime.datetime(2012, 8, 8, 21, 46, 24, 862000) is not JSON serializable

What can I do such that my dictionary sample can overcome the error above?

Note: Though it may not be relevant, the dictionaries are generated from the retrieval of records out of mongodb where when I print out str(sample['somedate']), the output is 2012-08-08 21:46:24.862000.