Allow all-day events to start at the left margin instead of indenting them to line up with events that have a time in front of them.
Some characters from languages other than English do not display correctly. Add support for them.
Update: A large number of languages are now supported by the website and the newly added “DejaVu” family of fonts.
Create more font options, perhaps some that are on the local machine.
Update: The “DejaVu” family of fonts have been added.
Allow for other combinations of start and end time, displaying am/pm, or omit the event time altogether.
Provide an option to include location information on the calendar.
Perhaps a one day per page with times marked out or an Agenda view where the events of the day are listed in order.
Printing all the events for a single week instead of a whole month would be nice.