party trick to shut up the non-believers

[robin at digininja.org (Robin Wood)]

Hi
At a party the other day I was asked the normal question of what do I
do for a living. I said security and kept it a bit vague but was
pressed so explained what pen-testing is and roughly what I do. I then
got the challenge, prove it, prove you can hack a company.

People would say to a dentist, prove you can do a filling but this
person insisted they wanted a demo. I explained the legalities and
finally fobbed them off and got away but it got me thinking, has
anyone got any good party tricks that they can pull in this kind of
situation that give an instant wow but are easy to do and legal? Not
quite legal but I was thinking if I knew any big sites with XSS I
could rewrite but none came to mind at that time.

Robin