/usr/local/lib/python2.6/dist-packages/pymongo/message.pyc in insert(collection_name, docs, check_keys, safe, last_error_args)
     65     data = __ZERO
     66     data += bson._make_c_string(collection_name)
---> 67     bson_data = "".join([bson.BSON.encode(doc, check_keys) for doc in docs])
     68     if not bson_data:
     69         raise InvalidOperation("cannot do an empty bulk insert")

/usr/local/lib/python2.6/dist-packages/bson/__init__.pyc in encode(cls, document, check_keys)
    460         .. versionadded:: 1.9
    461         """
--> 462         return cls(_dict_to_bson(document, check_keys))
    463
    464     def to_dict(self, as_class=dict, tz_aware=False):

InvalidDocument: Cannot encode object: datetime.date(2010, 10, 27)