This is my edited version of a lesson I found on here a few years ago. I couldn't find the post I got it from, so apologies for not referencing the original creator.
Basically go through the PPT with the students and get them to fill in the blanks, then get them to write two sentences about pictures you show on the board.
The final activity involves one student facing away from the board while you show a picture to the rest of the students. They will describe the picture to the artist and the artist will attempt to draw it. At the end of the time, you get the artists to show their pictures and say a sentence about it. Then choose the best artist for points.

The last activity is usually a lot of fun for the students and the class goes quickly.