I was just playing around with your dates in August 2011 at Kayak and found that the Hotel Marlowe in Cambridge was pricing out at about $153 per night (for a four star hotel.) I have heard great things about this hotel and it is near alot of public transportation and cultural activities including the Boston Museum of Science.
When you click on the select button on kayak it refers you to Skoosh.com which I have just recently heard about but have not yet booked anything through them.
Maybe some other here have had some experience with Skoosh or Hotel Marlowe, but it sounds like a great deal to me!
