Google Calendar for Chrome

Google Calendar (by Google) is a simple extension for Chrome that lets you access the popular Google Calendar in just a click, no matter which website you are at.

You just have to click on the icon next to your search bar to check if there's any upcoming event. Naturally, you have to previously link your Google account to the extension.

One of its great advantages is that it lets you add new events by just clicking on the icon. Nonetheless, the list of websites that support it is pretty limited, at least by now. Apart from this, the extension was created by Google itself, so it will certainly improve in later versions.