A very simple, yet stylish calendar.

calendar.py

# -*- coding: utf-8 -*-

# Copyright (c) 2013 Hugo Osvaldo Barrera <hugo@osvaldobarrera.com.ar>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

from PySide.QtGui import QCalendarWidget, QMainWindow, QApplication, \
    QVBoxLayout, QWidget, QGridLayout, QLabel
from PySide.QtCore import Qt

from datetime import date, timedelta
import sys

# TODO: update today when the day changes

class MonthWidget(QWidget):
    def __init__(self, today, month):
        super(MonthWidget, self).__init__()

        layout = QGridLayout()
        self.setLayout(layout)

        first = date(date.today().year, month, 1).weekday()
        # I start on sundays and count staring on one (not zero)
        first = ((first + 1) % 7 ) + 1

        if month < 12:
            last = (date(date.today().year, month + 1, 1) - timedelta(1)).day
        else:
            last = (date(date.today().year + 1, 1, 1) - timedelta(1)).day

        day = 0
        for i in range(0, 5):
            for j in range(1, 8):
                if i*7 + j < first:
                    continue
                day += 1
                if day is today:
                    color = "red"
                elif (j is 1 or j is 7):
                    color = "gray"
                else:
                    color = "black"
                l = QLabel('<font color="{}">{}</font>'.format(color, str(day)))
                l.setAlignment(Qt.AlignHCenter)
                layout.addWidget(l, i, j)
                if day is last:
                    break
            if day is last:
                break


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.centralWidget = QWidget()
        self.setCentralWidget(self.centralWidget)

        # # Main Layout
        # layout = QVBoxLayout()
        # layout.setSpacing(0)
        # self.centralWidget.setLayout(layout)

        # cal = QCalendarWidget()
        # cal.setSelectionMode(QCalendarWidget.NoSelection)
        # cal.setHorizontalHeaderFormat(QCalendarWidget.NoHorizontalHeader)
        # layout.addWidget(cal)

        self.setStyleSheet("QWidget { background-color: white; }")

        layout = QGridLayout()
        self.centralWidget.setLayout(layout)

        this_month = date.today().month
        today = date.today().day

        month = 0
        for r in range(0,3):
            for c in range (0, 4):
                month +=1
                m = None
                if month is this_month:
                    m = MonthWidget(today, month)
                else:
                    m = MonthWidget(None, month)
                layout.addWidget(m, r, c)



app = QApplication(sys.argv)

w = MainWindow()
w.show()

sys.exit(app.exec_())