Being unable to browse Newgrounds, I decided to check out my Indie sites. One of them, TIGSource (TIG = The Independent Gaming) had a annoucment that tickets for TIGJam UK 3 was available.

I'm not sure about the details of what the convention/event although looking at previous TIGJam events I did come across this:
"Bring your projects to work on in the company of your fellow indie developers, or start new ones!...A great time to get some feedback. For everyone else, just be ready to have fun, make friends, and create some cool stuff. Sleep is totally optional."

Tickets are VERY cheap, but that's probably because the hostel prices (if you plan to stay over) won't be (though having stayed in a hostel for a convention, it's not too bad either).

For the small details - http://www.tigsource.com/2010/05/06/tigjam-uk-3/
For buying a ticket - http://forums.tigsource.com/index.php?topic=11963.0