Crook Cottage (now renamed the Old Cottage) is another surprising sight, that just pops up as one turns a corner in this historic town. It was a town lock-up in the 1780s. 'Crook' is Australian slang for 'out of sorts', so it seems an apt name for this rather warped structure!
There are plenty of publications written about the town, including An Historic Trail, sponsored by the local civic society. Worth buying, and taking the walk I think.
Link: History of Penkridge