Tackk is a nice service for creating simple webpages, announcement pages, and digital portfolios. I've featured Tackk a couple of times in the past. The latest update to Tackk introduced an RSVP option.
When you create an announcement or event page on Tackk you have the option to use an RSVP widget. The RSVP option allows visitors to specify how many people they are bringing to your event and to enter comments like, "I'll bring cookies to the bake sale."
Applications for Education
Creating a Tackk event page with the RSVP widget could be a good way to quickly advertise a school event and get a sense of how many people will attend. As I hinted at above, Tackk event pages could be good for advertising and organizing an event like a PTA bake sale.