It is visually customizable and exposes hooks for user-triggered events

FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar

Google Calendar через Твиттер.

Add Sports Team Schedules, Birthday Reminders, And More To Google Calendars by @erickschonfeld

Never Miss a Game: Google Calendar Adds Sports Schedules -

хочу такой - Ink Calendar чернильный календарь