The Village Underground site was open during last year's Open House weekend. I went and it is well worth a visit - not least for the fun of sitting in the driver's seat of one of the carriages. This is much better than the mock-up in the London Transport Museum. (If you happen to want to be a tube driver).
I've recently learned that the Wood Green noticeboard photo whilst posted on the Going Underground blog was originally by Martin Deutsch and posted on Flickr. See link added beneath photo above. Thanks for the photo Martin.