If so a lot of the Membership could purchase business cards at a nominal cost and ask the potential new member to check out the site.
On the business card the TUG MEMBER could put his or her USERNAME on the back and request that "if" the NEWBIE decides to join use the TUG MEMBER's USERNAME as the referring member.
There are many TUG MEMBERS who could thereby become Lifetime TUG Members. The TUG MEMBER benefits by reducing the cost of membership and TUG would benefit by dramatically increasing the number of members.
Once you get the logo finalized we need to get those business cards set-up with a few simple instructions for the newbie on the back of the card.
A few hundred two color business cards with the tid-bits on the back and a specific blank line for the card purchaser to put his or her USERNAME would get the ball rolling.
Some ideas for the back of the card: