I also used the pumkin song. The kids loved it. For the warmup I used Sesame Street's video "These shoes are too big" to introduce the concept of big, bigger, biggest.
http://www.sesamestreet.org/video_player/-/pgpv/videoplayer/0/b3448501-1597-11dd-b10a-6119e86ae19b/these_shoes_are_too_bigI played the whisper game and the chopsticks game. The kids really enjoyed it.
Whisper game: Divide students up into groups of 4-6. The teacher whispers an expression to the first person such as "Look at the pizza! It's big." Give them 30-45 seconds to whisper the correct sentence down the line to the last person who says the sentence out loud. The team who says the correct sentence wins.
Chopsticks game: Divide students into 2 teams. Boys v. Girls works well. Each team gets a pair of chopsticks. At the end of the room on a table lay out pictures with big and small versions of familiar objects. In this case I used pictures of animals and fruits that the students learned in previous chapters. One student from each team waits for the teacher to tell them which item to retrieve. For example, "Apple". The students race to the table to find the apple. There is a "big" apple and a "small" apple. The student has to retrieve either one with the chopsticks and race back to the teacher. In order for them to get a point they have to say the correct expression "Look at the apple! It's big [or small, depending]."
