There are a great many groups to which people belong which do not issue membership cards. Proving to new aquaintances that you are in fact a member of one of these groups can prove difficult.
Enter the Membership Authenticator Card. Run by an independent but trusted group, these cards have your name, a photo (if desired), a shiny hologram showing the card to be genuine and (most importantly) the name of the group, or groups, to which you belong.
When you apply for a card, the Authority makes stringent checks to see that you are actually a member of the group. They will, for many cases, go directly to the group and ask if you are a member. Your photo will also be checked during this stage. Once your membership has been authenticated, the card is printed and you can show it to people as you wish.-- dbmag9, Sep 29 2007 What sort of groups are you talking about? "Senators (not) Looking For A Good Time In Airport Bathrooms"?-- Galbinus_Caeli, Sep 30 2007 I was thinking more along the lines of Mensa (although they do give cards, just crap ones) and possibly certain jobs.
If you really need a card to prove that you're not a senator looking for things that other people might find objectionable, I'd suggest the Membership Authenticator Card Company's more spurious cousin, the Antisocial Activity Alibi Association.-- dbmag9, Oct 02 2007 random, halfbakery