You'll probably see a post about this on a lot of blogs, but it's quite a good deal so I thought I'd post it here just in case you miss it.
From 17-31 July, you can take unloved make-up items (any brand, any condition) to Illamasqua counters, and in exchange for each item you turn in you'll receive a 25% discount on one Illamasqua product of your choice. There is no limit to the number of items you can submit for 25% off a new Illamasqua product. Unfortunately this doesn't apply to the online store - it's at counters only.
Illamasqua is known for its bold and unusual colours, but they do some very lovely neutrals too - I particularly like Unrequited pink powder blush, Sophie black medium pencil and Succumb (nude peach) and Truth (grey brown) eyeshadows.