Most properties can be bound, including many that you would never want to - but the 'Bind to' widget is normally hidden for these. It defaults to shown on the 'data' properties you'd normally bind to, such as GtkEntry.text and GtkCheckButton.active.
A bonus of this is you get 'guards' (where one toggle affects the sensitivity of an area of the dialog) basically for free. Just bind the 'sensitive' property of the container widget to the same key as the toggle, and all of its children will be disabled/enabled appropriately.
Last week I stayed a few days with my parents in Wales. Generously the sun came out and I got out a bit.
This week I am headed to Glastonbury! I like to get to lots of festivals every year and Glastonbury is far and away the best in the country. I often work at them but I'd hate to do that at Glastonbury, there's already not nearly enough time to see the whole of the festival. It just so happens there are several recently reformed big-name bands playing this summer, I think it is going to be one to remember!