One of my foundational rules of classroom engagement is simply this: never be the first one to open your mouth and start talking about any topic. Twenty years in the classroom taught me that one. Never assume. Never take prior knowledge for granted. Listen first, then act. Never presume to know what the students in front of you are capable of. They'll show you if you are bold enough to listen.

The UK's Medical Research Council publishes a "Biomedical Picture of the Day" (BPoD). The picture of the day for June 3rd was one of mine:

A very cool dynamic data set laid atop a map of the streets of New Your City... "New York City's urban forest provides numerous environmental and social benefits, and street trees compose roughly one quarter of that canopy. This map shows the distribution and biodiversity of the city's street trees based on the last tree census."