Hotel giant Accor calls this a "Crazy Prices" promotion, and crazy it is -- crazy good.
From now through June 16, you can reserve rooms at 800 hotels run by Accor, which includes brands such as Novotel and Mercure, for half off the usual listed rates. There are some stipulations (you knew there had to be some). Namely: While reservations must be made by June 16, the 50 percent discounts are valid only for hotel stays between July 8 and September 6. Also (and this caveat could be a deal-breaker for some), to get the discount, you must prepay for your stay, and reservations cannot be changed or cancelled. So if your plans change and you don't wind up at the hotel on the day of your booking, you're totally out of luck and you don't get any money back.
But for travelers who are fairly certain they can stick to their itineraries, the opportunity to snag a room at half off the usual rates outweighs the risks. For example, while browsing, we found a room at a Mercure hotel 200 yards from the Coliseum in Rome for $122 a night in August. If you want to reserve a room with no penalty for changing or canceling at the same hotel, the best rate available rate was $244.
Accor has a particularly impressive range of hotels in Europe, but it also has properties in major cities in North and South America, the South Pacific, and beyond. Again, to get the deal, you must make your reservation (and pay in full) by June 16. You can hunt for Accor hotel deals here.