How to run methods of an ActiveResource object?

How do you run the methods of an active resource (rest) object?

ie.

if i have

new = Person.find(2) # make REST call

can i just run? :

new.do_something

or is it more complex than that to run the methods? how does it work? or
can you only CRUD with active resource objects?

Any help is appreciated

Tahnks
Chris