Rather than waste those extra few minutes I might have with some students, I will often project interactive games onto the smartboard. My students know that when they see a game, they may play it.
What is really fun about these games is that it creates a competitive edge among the students. Can you beat the best score? Can you improve on your last score?
The games I project will always have something to do with what they are currently learning. Vocabulary, grammar, verbs... you name it!
My two favorites are quizlet and classtools.
With quizlet, I create a set of flashcards. Sometimes I will purposefully set them up to not just be translations, but sometimes of verb conjugations or even question/response type things. I then set the quizlet set to the game of "scatter" and students can play it on the white board when they walk in. This is also great because students can make their own sets on quizlet and play games even at home on their computers.
With classtools, you can create TONS of different interactive games. My favorite is the dustbin game. This game is great when you have categories of things. Students must drag the terms into the correct "bin" (category). This is also a timed race.
I noticed an exponential improvement on many topics when I put these games on the board at the beginning of the hour. The competition drives students to remember the terms. I also use this as something to do if there is a few minutes to kill at the end of an hour as well.
Check them out!