The point to this is to hand out a gmail invite to the person who completes a challenge you set.

Anyone can post a challenge. The idea is similar to gmail swap, but I don't get anything in return.

Here's one from me:
How long does my brother's MkII Ford Cortina take to get from 0-60mph on slicks ?

First person to post the correct answer gets a free invite.

If you put up an answer provide your e-mail address (although feel free to disguise it such as having xyz@___h__o__t__m__ail.com delete the _).

See my post at http://slashdot.org/comments.pl?sid=95978&cid=8218779
claiming prior art in this respect. Mad !?