If you register at http://www.feastoffootball.co.uk
and use 6 points (3 codes from kelloggs 750g packs) you can claim 60 minutes of 5-a-side football any day before 4.30pm, at any of Powerleagues 44 all-weather centres. http://www.powerleague.co.uk/home.html
As an example packs of 750g Frosties/Cornflakes and Crunchy Nut are £2 at Tescos.
I'm not sure how much pitch hire is nowadays but £6 split between 10 people seems good value and you can eat all the cereal afterwards :)