Good job, and example of the flexibility of simple web app + decent API - you've given me a great service, and I can hook it up to my own workflow exactly the way I want, rather than hassle you for features that only suit my own use case.
Would definitely code up a proper home page that explains the features (and perhaps why it's not a direct replacement for something like Google calendar). For instance, the CSV reports are really important for me (and I'm sure others) for whipping up those invoices at the end of the month.
EDIT: not sure if putting the current date as a fragment on the default URL is a good idea - it makes it hard to bookmark.
http://yfrog.com/z/gy5gxvxj