a) mentioning new vocab off-the-cuff (or in response to a question) in class and immediately showing a picture of it

b) students trying to remember a word and me showing them pictures of words they are guessing until they see the right thing

c) Us making up sample sentences on-the-fly and using a background picture as an impromptu slide: "Darth Vader is hungry. He could make a sandwich. He may toast some broad. He might eat it later": http://darth.vader.bread.jpg.to/