Earlier this year, a colleague and I paid a visit to Zappos, the online shoes and clothing retailer, where they do "culture tours" of their headquarters. Zappos has been doing these tours for quite a while now as part of its Zappos Insights service. I wrote about Zappos Insights here way back in 2008, and also in my book, Innovation X. It's a great example of a company taking its internal strengths and making them external in order to monetize them.
They do several free tours a days, you just need to sign up in advance (they do book up 2-3 weeks in advance from what I can tell). You can go as an individual or as a larger group.
The guides are high energy and fun, and have mostly been at Zappos for a number of years. So far as I can tell they rotate through doing Zappos Insights - this means you are getting to meet the real people doing the work, not people who have only been hired as tour guides.
Our guide was very open to any questions we had, and there was no obvious holding back on answers. She took us around various parts of the building - office spaces, common areas, cafe, etc. The Zappos staff just continued doing their thing - they are obviously used to being part of a zoo exhibit!
In addition to the free tour, my colleague and I paid for one-on-one meetings with managers in specific domains. When booking you can select which of several domains you want to do a deep-dive Q&A on. In our case we did user experience design and call center management. These got quite in-depth, and was a very worthwhile addition.
At least back when I did it, the sign-up page seemed unnecessarily complicated when it came to registering for both the free tour and the paid one-on-one. The follow-up emails were surprisingly sparse on helpful information about finding the building (since it's not that obvious from the street that it's the Zappos HQ) and what to do once you arrive on-site. (It looks like the tours page has been updated since then, with a clearer distinction of tours and the paid Q&A sessions, so maybe it's improved compared to my experience.) However, once in the lobby the staff were very helpful and gracious - they even provide a free shuttle back to the airport.
I would say that if you're coming from a fairly progressive company or almost any tech start-up or company based in the San Francisco Bay Area, much of the stuff on the free tour will feel very familiar: creating a collaborative and fun culture, free snacks, personalization of the office/space, the various amenities and services to employees. But I can recommend the in-depth domain Q&A sessions even if the tour itself isn't breaking new ground for you.
Find out about the tours and booking here.