gistfile1.py

# coding: utf-8
import calendar

YEAR = 2013
MONTH = 1

c = calendar.Calendar()
dt_calendar = c.monthdatescalendar(YEAR, MONTH)
int_calendar = calendar.monthcalendar(YEAR, MONTH)

calendar = [[None if int_calendar[dt_calendar.index(week)][week.index(day)] == 0 else day for day in week] for week in dt_calendar]

print calendar

gistfile2.pytb

[[None, datetime.date(2013, 1, 1), datetime.date(2013, 1, 2), datetime.date(2013, 1, 3), datetime.date(2013, 1, 4), datetime.date(2013, 1, 5), datetime.date(2013, 1, 6)], [datetime.date(2013, 1, 7), datetime.date(2013, 1, 8), datetime.date(2013, 1, 9), datetime.date(2013, 1, 10), datetime.date(2013, 1, 11), datetime.date(2013, 1, 12), datetime.date(2013, 1, 13)], [datetime.date(2013, 1, 14), datetime.date(2013, 1, 15), datetime.date(2013, 1, 16), datetime.date(2013, 1, 17), datetime.date(2013, 1, 18), datetime.date(2013, 1, 19), datetime.date(2013, 1, 20)], [datetime.date(2013, 1, 21), datetime.date(2013, 1, 22), datetime.date(2013, 1, 23), datetime.date(2013, 1, 24), datetime.date(2013, 1, 25), datetime.date(2013, 1, 26), datetime.date(2013, 1, 27)], [datetime.date(2013, 1, 28), datetime.date(2013, 1, 29), datetime.date(2013, 1, 30), datetime.date(2013, 1, 31), None, None, None]]