How can I model this relationship?

My database design skills are a bit rusty so I was hoping to get some help from y'all =)

I have a 'user' table that contains all the typical fields (id,name,email,etc.). Users can have many 'invitations'. (many to one) Each 'invitation' has a single owner (user). However, a single 'invitation' can have many 'invitees'.

My confusion is this: If users can have many invitations and invitations can only have one owner (user) but that single invitation can contain many invitees (these are users) how should this be modeled? Do I need a new table?? ('invite')

I hope my question makes sense.

If an invitations is just an invitation, then it seems simplest to store all of the users for an invite in their own row in a separate table.

Users
 - UserID, PK
 - other details about the users

Invitations
 - InvitationID, PK
 - OwnerID or OwningUserID or just UserID, FK to Users
 - other details about the invitations

InvitationUsers
 - InvitationID, FK to Invitations
 - UserID FK to Users
   [PK on (InvitationID, UserID)]

A lot of people are tempted to store all of the users of an invitation in a comma-separated list or as XML. Resist this temptation; it leads to nothing but trouble.

If there is only a single type of invitation (like "be my friend on Facebook and we can hug and all that") then a simpler model might be:

Users
 - UserID, PK
 - other details about the users

Invites
 - SenderID, FK to Users(UserID)
 - RecipientID, FK to Users(UserID)
   [PK on (SenderID, RecipientID)]

If an owner can send an invitation to various things (a dating service, a boat show and a movie) then we'll need more details about what those relevant things are.

StackExchange Database Administrators Q#4418, answer score: 3