Heritage Open Days are a set of tours or special openings of buildings around the country for four days every September. This year’s itinerary is now out and there are six pages of search results local to Birmingham (can’t create a permalink you’ll have to go to the search page and use “Birmingham” as a keyword).
Highlights that I’ve seen so far:
Birmingham Bonanza Walk – architectural walk around the city centre that pays attention to the modern as well as the past.
J W Evans – historic factory in the Jewellery Quarter.
Handsworth Old Town Hall – no excuse, it’s on the 11 route.
There’s also a walk entitled “Birmigham More Canals Than Venice”, which I can’t find online at the officlal site but is here.