Credit:
More Google calendar updates--you can now send updates to your Google calendar using SMS.
This works by sending a text message to 'GVENT' along with the event details, and it will be added to your Google calendar. You'll also get a text message confirmation back. In addition, you can access your calendar's information. Texting the word "day" will return a message with all of your events for the day, and "nday" will give you all the events for the next day.