Simple filter to get activity count for a given day.
    Defaults to today.

def show_activity_count(date=None):
    """
    Simple filter to get activity count for a given day.
    Defaults to today.
    """
    if not date:
        today = datetime.datetime.now() - datetime.timedelta(hours = 24)
        return Activity.objects.filter(timestamp__gte=today).count()
    return Activity.objects.filter(timestamp__gte=date).count()