[silurius]

Syndication-type features I'd look for would be:

• Outbound and inbound Javascript, RSS or XML syndication of calendar content
• Some synchronization intelligence - updated events on one site carry changes to syndication recipients
• Flexible content type - e.g. events, news stories etc. as suggested above
• Customizable calendar fields to classify events
• Meta search capability - for example, pick an area of interest and an entire, current month calendar would pop up for that subject or theme.
• Integrative features to support some degree of compatibility with other calendar systems (e.g. Drupal Events project)

I am ok with the idea of some of these features being vBulletin only at this stage, given the potential complexity of integration with other platforms. (However I suspect the built-in syndication features which already exist could support external feeds with relative ease).

Areas of expansion that are also intriguing to me:

• Flexibility of calendar systems (see this site for a semi-comprehensive list). Ability to customize length of year, month, etc. This would not only support scholarly special-interest sites, but religions who observe non-Gregorian calendars.
• Ability to define historical timeline based on specific calendars, and to call on specific areas of this timeline in posts, when relevent discussion topics come up. Visually and structurally, this thing is kind of what I am thinking of.
• This is one example of what someone I'm working with refers to as his baseline for what he wants to accomplish: www.cosmopolity.org

Been chatting with folks associated with CivicSpace Labs, who are very excited about building a meta-calendar, and although I have faith that they can probably pull something off, I've also observed that vBulletin developers seem to be able to roll things out far more quickly and effectively in some cases, probably for multiple reasons.