Ported John Resig's Javascript pretty_date function to Python.

gistfile1.py

from datetime import datetime
import time
import math

def pretty_date(t):
    """
    Take a datetime object or epoch time int, return a string representing
    how long ago the date was.

    Inspired by: http://ejohn.org/files/pretty.js
    """
    if isinstance(t, datetime):
        t = time.mktime(t.timetuple())

    diff = time.time() - t
    day_diff = int(diff / 86400)

    return day_diff == 0 and (
            diff < 60 and "just now" or \
            diff < 120 and "1 minute ago" or \
            diff < 3600 and "%d minutes ago" % int(diff / 60) or \
            diff < 7200 and "1 hour ago" or \
            diff < 86400 and "%d hours ago" % int(diff / 3600)) or \
        day_diff == 1 and "yesterday" or \
        day_diff < 7 and "%d days ago" % day_diff or \
        day_diff < 31 and "%d weeks ago" % math.ceil(day_diff / 7) or \
        "%d months ago" % math.ceil(day_diff / 30)