Tintin
Google
This is a great museum, with free entry. It is spread out over one large floor, which is divided into separate sections.
There are lots of fossils and preserved creatures, as well as lots display cabinets. There are plenty of posters offering information, as well as many interactive screens.
Due to this being one of the smaller museums in Cambridge, I found it much easier to walk around and actually learn things.
There are some great displays throughout the museum, as well as a nice little gift shop. Worth a visit and a great place to spend a few hours.