Simple create an event with guestlist and signup.
Darkpage Simple Eventer is an simple event script that alows you to add an signup form to any post you want. It includes the form with 3 awnswer types and shows the Guest list.
Add [dpe] to your post to include the signup form.
v1.0 1st release
v1.2 Bugfix: Fatal error on load. Add: English support