I looked at the Seed Code calendar too. The functionality looks great, but you pay for it.
Did you Google "Filemaker Calendar"?
When I did this basic search, I came up with http://www.fmcalendar.net/
which has a single price regardless of users. Although it's a personal preference, I like the idea of paying a single fee for a product rather than having to pay for each user, for example, and then maybe even have to pay annually or other subscription.
HOPE THIS HELPS.
Please also check out our product - soSIMPLE Calendar.
It's a very powerful web viewer & web-based calendar that's also very affordable. You can try out many of its features right on our web site http://sosimplesoftware.com/try
It handles resources, has an extremely flexible timeline view, and a unique maps view where you can show events for a given timeframe together on a Google map.
It's designed for integration See our tutorial for a 5-minute integration.
It works within FileMaker (standalone or server-based), on your web site, on your phone, and as an iCal feed.