During Halloween Alton Towers Theme Park is open until 9pm each night, with lots of really cool additional entertainment and scary mazes! Until 4pm tomorrow they have a "hidden" Half price ticket - you just need to look behind day 9 of their advent Calendar.... http://www.altontowers.com/interactive/scarefest-countdown/
This offer appears to be live until 4pm tomorrow - they put on their facebook page that it will be replaced by a 20% off discount from then onwards!
We went to Halloween last year and really enjoyed it - deffinately the best time of the year to visit!!