Hilton is currently offering a new flash sale across the EMEA region (Europa, Middle East and Africa). Rates needs to be booked by October 17th for stays between October 19th, 2012 and December 29, 2013! 
There’s a weekend requirement for hotels in Europe and no restriction for Middle East and Africa.
And not every hotel does participate and even when, the flash sale rate is not available on all possible dates. But if you’re staying in this region it might be a bargain. But remember:
Full non-refundable prepayment required at time of booking. In the event of cancellation, refunds are limited to ten percent (10%) of the total prepayment (only for hotels in Germany).
Here is an example of participating hotels in Germany (first price row is “room only”, second row “Room with Bed & Breakfast”):
And here’s the London area:
Abbreviated Terms and Conditions Offer is subject to availability at participating hotels within the Hilton Worldwide portfolio of brands in the UK, Europe, Middle East and Africa. Book between October 15, 2012 and October 17, 2012 (offer closes midnight GMT +1). For participating hotels in Europe, stay on weekends between October 19, 2012 and December 29, 2013 except as otherwise indicated. For purposes of this offer, “weekend” is defined as Friday, Saturday and Sunday nights in Europe. For all other participating hotels, stay between October 15, 2012 and December 31, 2013. Full non-refundable prepayment required at time of booking In the event of cancellation, refunds are limited to ten percent (10%) of the total prepayment (only for hotels in Germany). Discounts vary and range from 15% to 40% off select rates. Offer not available for stays on 31 December 2012. Other blackout dates may apply based upon which day of the week a stay is consumed, geographical location of hotel and/or by brand. Additional restrictions apply. Before booking, please click here to see full offer terms and conditions.
Regards,
Dieter