I do these steps lots of time and it's doesn't work, why? I 'm using galaxy s 1 with: 4.2.1 and CyanogenMod 10.1
on computer with internet browser open up google calendar
click on gear emblem settings
click setting
click on calendar (blue color)
click Browse interesting calendars »(blue color)
click More (blue color)
on Contacts' birthdays and events ..click subscribe
than on your Device
open up the calendar app
hit the three dots
hit Calendar to display
put a check, Contacts birthday and events
hit Calendar to Sync
hit ok
then your done
on computer with internet browser open up google calendar
click on gear emblem settings
click setting
click on calendar (blue color)
click Browse interesting calendars »(blue color)
click More (blue color)
on Contacts' birthdays and events ..click subscribe
than on your Device
open up the calendar app
hit the three dots
hit Calendar to display
put a check, Contacts birthday and events
hit Calendar to Sync
hit ok
then your done