Please give me a list of 20 GOOD web sites that provide useful
information on  the charles hotel in cambridge, and on finding the
discount rates for hotels in general.

For each URL you give, please tell me why it's good - what do they do,
why I should trust them or spend my time reading their opinions.
Please always give the full long URL address for pages with
information that I should know about, do not just send me to the site
to figure out stuff myself.

Many thanks in advance.