A co-worker at my school came up with this brilliant idea that she uses for teaching her students new vocabulary in reading groups.
First, she created a grid sheet and in one she writes all the new vocabulary words and in the other all the definitions that go with them.
Then, the kids cut out the vocabulary word boxes and tape them over the definitions, allowing them to still open (see bottom left box).
Then with each child having a board (sometimes they work in partners) the teacher either calls out a word or says the definition and the children have to call out the matching answer, without flipping up the little window. If they get it right they put a token over the word. It's kind of like Bingo, but we just say the first person to get 5 or 6 correct wins. If no one can guess correctly I let them flip up the window to look. Allowing the windows to flip up, gives them a way to study them too.
It's totally amazing how much fun the kids have and that they actually LEARN these new words. It's been so successful that I expanded it to math, social studies and science vocabulary. It's so simple, but the kids LOVE to play it.