A possible concise summary is:
A boy named Cody gets accepted into Harvard for the summer, but his friends Junior and Joseph try to stop him from going by throwing grass on him and making him confess to cheating. Cody's parents sell their house and move to Bosnia, thinking it's near Harvard. The principal revokes Cody's acceptance after seeing the video of him cheating. Cody decides to stay with his friends and do fun stuff instead. The cop who came to arrest Cody gets high from the grass.
Here are the key facts extracted from the text:
1. Cody got accepted into Harvard for summer classes.
2. Junior and Joseph tried to stop Cody from going to Harvard by various means.
3. Cody's parents sold their house and moved to Bosnia to be near Cody.
4. The police officer ate some grass that Junior and Joseph threw on Cody.
5. Cody decided to stay with his friends instead of going to Harvard.