It's easy enough to add events to Google Calendar, and you can even do it from your email. If you use Chrome, there's another way to add events quickly directly from your address bar.
How-To Geek walks you through the process, which involves creating a new search engine in Chrome's preferences. You add a name and shortcut for the new search engine, then copy the URL Calendar users for new events:
From there, you can just type in your shortcut from the address bar, then type your event, complete with time and date, then hit enter. You still have to save it in Calendar, but this eliminates having to navigate to Google Calendar to begin with. To check out the complete shortcut, head to How-To Geek's post below.