I've still been a bit shy of making things in blender.

I've still been a bit shy of making things in blender. This video shows me how easy it would be to make air-conditioning ducts (and lots more).

Also, this silent video:
https://www.youtube.com/watch?v=uyph2GK85vo
and:
https://www.youtube.com/watch?v=AMXcQ2V-VGA
https://www.youtube.com/watch?v=mhLdPSZuNac&feature=share