Chrome Page Notes lets you take notes for Web pages as you visit them and access these notes later when you visit those Web pages again. It provides visual cues to let you know if there are notes available for the Web page that you're on. You can choose to sync your notes automatically to your Google Docs account. You can configure multiple computers to sync to the same account, and thus keep your page notes synced across multiple computers.
Google Calendar Chrome Extension adds a button to your browser toolbar that displays a preview of your calendar while you're navigating. (works on any page). If you're on certain sites where it detects the presence of events, the icon changes to a green "+". Clicking that icon lets you add the event to your Google Calendar, and shows you a Map (if there's a location it could detect.) Supported sites include Facebook, Evite, and any site that uses the hCalendar microformat or derivative microformats such as hResume.