Easy to use rsvp plugin originally created for weddings but could be used for other events.
This plugin allows you to add RSVP and guestlist functionality. Guests can leave custom messages for the planners. Uses Google Docs spreadsheets.
A Robust RSVP plugin
This plugin allows the Roxi widget to be quickly and easily inserted into any page or post. Requires a venue account at getroxi.com.
**BETA - Do not use for production yet** RSVP Bee is a management tool for keeping track of wedding guest lists and guest RSVP.