Whenever possible and appropriate, I try to bring food into the classroom. Students are automatically more engaged in the lesson and it's a great motivator (if you don't do your best, you don't get the treat).
One of my favorite things to do is use Hersey's kisses as a concentration game for math. I use the white version of these:
I put the stickers on the bottom of the candies. I use multiplication facts for my fifth graders, but you can use any operation depending on your students' ability level. I put the product on one candy and the equation on another.
Students put the candies face down and play concentration. It's a great center for holidays or special occasions.
The prep work takes about twenty minutes and I'd recommend writing on the stickers prior to placing them on the candy.
(ELA connection: You could do Greek and Latin roots or affixes where students match the affix with the meaning)
I plan to do something like this around Halloween because the students will most likely expect candy so at least there is an academic purpose!