Instructions:(Originally via starving artist on MSE):
You can save 15% off adult tickets at Tutankhamun and the Golden Age of the Pharoahs exhibition at the O2 by calling Greenbee on 0845 610 0330 quoting 'GREENBEE TUTANKHAMUN'.
Offer details are on page 7 of the Greenbee directory found in the September/October issue of Greenbee's 'source' magazine from John Lewis/Waitrose.
Prices: Monday-Friday £12.75 | Weekend £17 (compared to £15/£20 without discount)
Exhibition from 15 November 2007 to 30 August 2008.
Next issue of 'source' magazine comes out 5 November so offer may finish then though 'strictly subject to availability'.
Works out much cheaper than Ticketmaster (as booking fees etc. less too).