But the realities of lesson planning, state-mandated curriculum requirements and student indifference often leave limited opportunity for impromptu lessons in current events.

Mollie trilled from the top of the stairs, interrupting their impromptu lesson.

Two or three impromptu lessons followed, along with some chamber music appearances, thanks to Liszt's recommendation.

Today's kids, Mr. Frederick said, often require impromptu lessons in dressing.

One day the teacher found and caught him, and decided to use him for an impromptu lesson on woggle-bugs.

In the process they found themselves giving impromptu lessons in design appreciation and decorating with - that 50's word - flair.

You see Betty Carter in a corner, giving an impromptu lesson to young kids.

The teacher invited us in and Rich gave an impromptu lesson on Australia's wildlife to excited six-year-olds.

They were having an impromptu lesson about recognizing emotions.

So an impromptu lesson followed on proving that the world is round.