This is my introductory PPT and lesson. I highlighted when to use some/a/an when requesting food and drink. I didn't give an explanation because my students wouldn't understand but I'm getting tired of hearing "I want some hamburgers" rather than "I want a hamburger".
Next on the PPT is a 'what's missing' game that I took from another poster from a grade 5 lesson (thanks a lot, it went over well). Have the students respond using the target expression "I want a ________" when they guess the missing food/drink.
Finally, a card game that I also took from another poster and adapted for this lesson. I included the directions at the end of the PPT and the actual cards in a HWP file. Basically the kids get into groups of 4,5,or 6. Teacher gives them the set of 8 cards. The kids play 'rock,scissors, paper' to see who goes first. The entire groups asks the winner "What do you want?". The student answers randomly and draws one of the cards. If the card matches the student's guess then he/she keeps it. If the card does not match the guess, the students returns it to the pile. If the student draws the bomb card he/she loses everything. My 4th graders loved this game a few months back.