Well worth going in, and if you can manage it, pick a windy day. When the sails are going round there's an immense sense of power. Yesterday they were only turning intermittently, so they weren't actually milling, but when the wind got up it was quite impressive, watching the sails go by the window. You can go right up top, and see the mechanism in the cap turning, and hear the creaking as the cap turns slightly with the wind. I'd never been in a working mill before, and was amazed.
We tend to think of the age of steam as the beginning of 'superhuman power', but forget that the wind was harnessed long before. Perhaps on a sailing ship you don't feel it the same, because you're being carried with it. Incidentally, they think it's possible that the main wooden shaft was a re-used ship's mast, from the days when the Ouse was a port for sea going ships.
There's a website:
http://www.holgatewindmill.org/index.htm
with the open weekends listed.
http://www.holgatewindmill.org/openday.htm
For Windy Miller fans: The Mill had another floor added by the Victorians, which raised the sails, improving the wind capture. It also had the benefit of placing the bottom of the sails above the height of the door. Apparently, mills often had sails sweeping past the door, and as the top turns with the wind, it was possible to not realize, step out, and be hit. When you see the size of the sails, and how fast they can turn, you can imagine the impact on a human....
