Sainsbury's are rolling out a pilot scheme to double up Nectar points - a bit like the Tesco Club Card scheme. Only in selected stores at the moment, but luckily for me my local store is one of them! What happens is you take your Nectar card to the desk, select which department you want to spend the points in - clothing, electrical, homeware - and then they subtract the points from your card and give you a voucher to be used at the till for twice the monetary value of the subtracted points!!
I used £20 worth of points to buy a camera for £40 and then £10 worth to put £20 towards a summer weight duvet and new quilted mattress protector All stuff I was wanting to buy very soon anyway