I was asked to help with the event and it was a very rewarding and enjoyable, if exhausting experience.
Many people came and published apps to the Windows and Windows Phone stores.
The feedback was very good and it was so popular we're doing it again.
If you can get to London on Saturday September 20th, why not come along. You'll go home with a swag bag and possibly phones and other goodies to if you submit to the store on the day.
Register at http://aka.ms/winappspublishhack.