My Mother of Thousands Kalanchoe flowered last year..

Is this unusual? It was of course very hot. My air plant flowered too.

 

I'm glad it flowered for you. It's a pretty inflorescence and not unusual for me, but I suppose it depends on the conditions the plants are kept in.
These grow like weeds in my greenhouse and I have to keep yanking them out of other pots and discarding them, but yours looks well behaved.

 

Possibly unusual when growing as a house plant, but kind of normal if growing in a greenhouse as Michael says.

 

Yep! I have one in the greenhouse too and I have to weed the babies out. I like it as a curiosity though.