Sharing calendar between hubby and I?

Hubby and I each have an iPad which we originally setup with individual apple Id's. Then I realized that if we use the same Id we can share games and apps etc. So i use his apple id to download new apps. However, we have each been using the original calendar that came in the iPad, and love it. But is there anyway that we can sync these calendars? Or similar easy calendar with monthly view in addition to all the nice features of the original ?
Thanks!

Have one of you use the gmail calendar and sync it. The the other one use iCal and you will have the option to sync one or both calendars to your iPad and look at them separately or put them both on.