It's an oldie but a goodie!

Theatre terms

In is down, down is front

Out is up, up is back

Off is out, on is in,

And of course,

Right is left, left is right.

A drop shouldn't and a

Block and fall does neither.

A prop doesn't and

A cove has no water.

Tripping is OK.

A running crew rarely gets anywhere.

A purchase line will buy you nothing.

A trap will not catch anything.

Strike is work. (In fact, lots of work)

And a green room, thank God, usually isn't.

Now that you're fully versed in theatrical terms,

Break a leg-but not really!