The students I teach range in age from 5 to 13. Their levels range from not knowing the alphabet to capable of carrying on short conversations. Now that I know more about this job, there are many things I wish I had brought that I didn't. I'll go ahead and tell you in case you are packing a passport on your way to distant lands.
Any card game with pictures on the cards are invaluable for vocabulary quizzes. Leave the Trivial Pursuit at home. A children's version of Scrabble would be a good way to teach them how to spell without them realizing they are learning. (Poor dears will believe they are just playing a game.) *smile* However, the older and more advanced students should play the regular version as the children's game rewards tiny words with big points....they'll stop trying to think of words with more than three letters once they realize this. Basically, what you need to do is go to the store and look at all the games. Think of how you can use them to teach words, concepts, anything to do with the English language. Also, I'll warn you right now that your students' levels are probably much lower than you imagine. Something else you should consider is the age range of your future students.
I always thought Dr. Seuss books were stupid and childish when I was a child. (I also suffered from delusions of being the world's most advanced reader while still in elementary school.) However, since I've been here, I've discovered what a fabulous teaching tool these books are....for teaching English as a foreign language anyway. While this school only has six Seuss books, they are easily the most beloved books on the shelves. When I bring the books into the classroom, the students all cheer because they know they are in for a treat.....poor things just don't realize that they are being educated behind their backs. *grin*

One book, Hop on Pop, is excellent for teaching the pronunciation of consonant/vowel blends. Another, Bears in the Night, tells a story entirely through the use of prepositional phrases. This may sound like it would put your students to sleep, but it's their favorite one.