Calcium provides interactive calendars you can use through your browser. Features include: dynamic calendar merging (events from one calendar can be included in another), multiple views and formats, repeating events, email support, extensive color and font customization, support for full HTML in the event text and calendar headers and footers, popup text associated with any event, searching and filtering, multi-language support, a flexible security model, and more. Calcium is very easy to use, and fully supported by an established company. It runs anywhere that supports Perl CGIs; no non-standard Perl modules are necessary. Full 2-way synchronization with Palm Pilots or MS Outlook is available; iCalendar "subscriptions" are supported too.