Update June 2013 - Unfortunately Keep and Share is no longer free. They do have a free trial period if you'd like to try them out.
Keep and Share is a free, online calendar that you can share or keep to yourself. It has a lot of nice features and is super simple to use but you might find yourself limited with getting just one calendar.
Using the Keep and Share Online Calendar
Creating a Keep and Share online calendar is incredibly easy to do. You'll just need to enter a name, include holidays if you wish, and then choose whether you want your calendar to start on Sunday or Monday.
After you've set up the calendar then it's time to enter some events. Click on the day you'd like to enter an event and start typing. The box you type in is actually a little word processor so you have some formatting options that you can use to set certain events apart from each other. You can even add pictures and icons if you'd like.
Your calendar can be viewed in month, week, day or event view and can easily be shared with others as either view-only or as a calendar that they can also edit.
Keep and Share On the Go
Keep and Share has a mobile website that you can access from anywhere on your phone or tablet computer. There are no apps out there for Keep and Share but the mobile site is nice and will get the job done.
You can receive email reminders for events and you control when you receive those email reminders. You can even choose to get a daily calendar update sent to you by email - perfect if you are sharing calendars.
Other Features of Keep and Share
Keep and Share is much more than just an online calendar. You can also use it to share files and photos, create to do lists, and keep online databases.
What I Think About Keep and Share
You only get access to one calendar with the free Keep and Share account and I found this very limiting. There are some ads with the free version as well but I didn't find them very intrusive.
I love the mini word processor that is available for entering events. I really can customize my events to look just how I want them to look.