Broke kids up into groups of 4 and made a set for each group.
Cut out all the parts for a snowman for each child: 3 "snowballs", nose, hat, 2 arms.
Each child in the group gets their large snowball to start the game. The rest of the parts for everyone's snowman go into a big container that you can't see through. I've used a Santa hat and a big paper bag. Shake up the parts, then the children take turns drawing parts out of the bag to assemble their snowman. They have to get the balls in order: medium then small. After that they just need to draw any missing part. If they pull out something they don't need, that part goes back into the bag and the next player takes their turn. Keep going until someone builds their complete snowman. I had candy canes for the winners. You can play multiple rounds depending on time.
Another game I played when my daughter was in 5th grade was Cranium's science game. I went through the game cards the day before and picked questions that I thought the kids would know and that were particularly gross. Broke the class up into teams. I would read a question, each group would discuss and come up with an answer. I then asked each group what their answer was and they got a point if it was correct. I think I asked about 20 questions. Winning team got candy bars. It was educational and fun at the same time. Kids AND teachers enjoyed it!
For the 5th graders, again...preferably something requiring minimal supplies...maybe holiday variations of existing games, like Duck, Duck Goose (though that would be too much for a classroom game for us!). TIA!