You've probably already finished planning all your Dr. Seuss activities but I'll share one I'm doing. My kids will do this activity in stations this week after reading Green Eggs and Ham.
I cut out pictures of food from magazines and grocery ads (great to do with the Sunday newspaper). I glued the pictures on half of an index card and wrote the name of each food. My kids will sort the cards on a Venn diagram pocket chart into thses groups: foods that are green and foods that I like.
If you make this be sure to find plently of green foods.
And here's the form the kids will fill out after sorting.