Thanks to Igor for an interesting source.
Tzvee Teaneck wrote an article on how to add Hebrew dates, Parshas and Daf yomi to your Google calendar.

Here you see how it looks on my Asus EeePC 701.
I have to say, that it pretty nice feature for those, who use Google calendar on a permanent state.

Installation is very easy:
(just copy/paste from Tzvee’s page)

To add them to your Google Calendar, select Other Calendars on the left and click on Add, then choose Add by URL and copy one from below, then click the Add Calendar button.
Copy the URL below (from the Google Help Forum 11/26/09 courtesy of a user named Ephraim):
Public Google calendar — Hebrew date. (It excludes times, holidays, and Torah portions so that it can be used together with other calendars in various locales)

http://www.google.com/calendar/feeds/qhasa5afg633voo8j26mf1ntjs@group.calendar.google.com/public/basic

Public Google calendar — Torah Portion.

For the Diaspora (outside Israel): http://www.google.com/calendar/feeds/olv18cdaciiflov66ah3qlkntk@group.calendar.google.com/public/basic
For Israel:

http://www.google.com/calendar/feeds/tuojqh14bvmhomns7dod9fqci8@group.calendar.google.com/public/basic

Public Google calendar — Daf Yomi.

http://www.google.com/calendar/feeds/v5bvdts4vlfhd2dfgdairv9t94@group.calendar.google.com/public/basic

Popularity: 85% [?]

calendar, google, luach