Plugin Needed for Signups and Sharing

Greetings WordPress Community:
I want to add a function to my site and was hoping that someone in the community could recommend a plugin that would do this.
I am a Meditation teacher. I want to give people a page to go to and tell others that they are interested in taking a class on a specific day at a specific time so that if there are others interested in this day/time, they can also sign up.
Think about someone who says to himself/herself, ‘I’m free today, but there are no Meditation classes on the schedule. But I would like to go to a Meditation class and wonder if others wish to join me today’.
So they would go to this page, add their name, day and time, and this would show this person registered. Then, others could visit this page and add to this list.
Ideally, this would work with a list of registered people. I use MailChimp for my newsletter.

Does anyone have any ideas on a plugin that would help me accomplish this?

many thanks for any help you can lend.