Based on Stijn Nevens and modified for Django use to round current time to the nearest 15 minute.
from datetime import date, timedelta, datetime, time
def roundTime(dt=None, dateDelta=timedelta(minutes=1)):
roundTo = dateDelta.total_seconds()
if dt == None : dt = datetime.now()
seconds = (dt - dt.min).seconds
# // is a floor division, not a comment on following line:
rounding = (seconds+roundTo/2) // roundTo * roundTo
return dt + timedelta(0,rounding-seconds,-dt.microsecond)
dt = roundTime(datetime.now(),timedelta(minutes=15)).strftime('%H:%M:%S')
dt = 11:45:00
if you need full date and time just remove the .strftime('%H:%M:%S')