I have a job interview but I dont know what the job is.. help?

It sounds like you'll be cold calling or being a salesperson (like door-to-door type) People who are elusive like this are usually part of a program that gives them rewards for recruiting new members and gets a percent commission on products sold through it's channels (website, catalog, etc). My advice: try to call first and ask what it's about. If they won't tell you what it is, then be prepared for disappointment.