MVC3 and User Model

I'm using the generic membership class and have had my user sign up for workshops.

I need to have something like this

User 1 --Workshop 1 --Workshop 2

--Workshop 5

User 2 --Workshop 1 --Workshop 2

--Workshop 5

How do i get the user model?

If I understand right you wnat ot extend the standard asp membership user. If I'm right, this answer should help you