Event Calendar ROR plugin

Question

Hi all,

I am working in ROR framework. I have a requirement to send invitation to a meeting event to the specific users.The event creation should be like in google calendar,hotmail calendar.

I need to send invitation through Email, selecting from the users list and i need to fetch their reply (whether they accept or reject the inviation) and i need to store the invitation in the user TODO list.

is there any plugin, where i can get most of the features above and extend it further.

thanks in advance, Mahesh