I recently was able to call in on the Newark Civil War Centre which is a must see for any ECW buff. My main focus though was on one of the two temporary exhibitions currently on: Cutting Edge, The Changing tools of War. It was focused mostly on the evolution of arms and armour during the Pike and shot, specifically around the ECW. One section was dedicated to objects associated with Thomas Fairfax including his own sword... and wheelchair
One fun element of the gallery was a jacket which could be filled up with sacks of sand so that the wearer could experience the weight of light buff jacket to a full suite of cuirassier armour. I could only personally go up to a buffcoat with breastplate and backplate
Also another gallery was dedicated to the evolution of British democracy including a a display of suffragettes clothes.
The main permanent exhibitions themselves are worth visiting as there are plenty of objects on display, a series of short films made to tell the story of Newark during the civil wars and an interactive app that can be used at various information points around town