Startpage UK has a cool competition going on. You can win 5 tickets for Sziget + plane tickets from London and back.
You just have to register, make the site your homepage, then invite as many friends as possible. One of the tickets will go to the user that referred the most friends, while the other 4 will be drawn at random.
If you want to register, just go here.
If you want to book a hotel for your Sziget stay, click here.