As an undergraduate, I often thought Green was perhaps the most beautiful college, though it doesn't look like a college at all. In fact, it does look rather like a stable block (which was the original function of the front buildings). We had a tour of the gardens, a brief presentation on the history of the observatory, and the opportunity to climb to the top of the "Tower of the Winds" whose restoration was being celebrated. The weather was splendid, and hence so was the view. Whilst the development director was rattling his tin can, that aspect was kept low-key. I speculated that the reason for the open day was that some public fund (e.g. English Heritage or the Lottery) might have stipulated it as a condition of funding. Betjeman rated the building the most beautiful in Oxford; Pevsner reckoned it was the best architectural observatory in Europe. (It was in use as an observatory from 1794 through to the early twentieth century).
We had lunch at Far From The Madding Crowd, a venue I discovered with uitlander on a previous trip. The food was good but, as with the bus, did take rather a long time to appear.
The remainder of the afternoon was divided between photo-opportunities, and a trip to the Botanic Garden. I don't think I had visited the glasshouses there before: they contain a more populist plant selection than those I have seen elsewhere (for example, I'm sure I've seen bananas and ginger at Kew, but Oxford also had cinnamon, cardamom and various sugar plants). On this occasion they also had a rather spectacular Bird of Paradise flower in full show.
We were both rather tired on our return, but it has been a good break from the week.