How the president is, and is not, like a soccer coach

Here's a li'l story about my recent adventures in a second grade classroom...
Someone from my accelerated Master's program came to observe me giving a social studies lesson. The lesson had to have something about reading or writing integrated into it, so I decided to craft the lesson around an issue of TIME For Kids magazine. The cover story on the issue I chose was on our new Supreme Court justice Sonia Sotomayor. (I like a challenge.)
I had a little time earlier in the day, before my observer came, so I asked students if they'd ever heard of the Supreme Court. A few could tell me a little bit about court and lawyers, including the tidbit that lawyers cost money. I also asked if they knew what "supreme" meant. I said they'd probably heard it in reference to pizza, and asked them to please not think of the Supreme Court as the Pizza Court.
As I was gathering this background info, one boy raised his hand and asked, "Do they have a president on the other side of the world?" I said this was an excellent question. We talked a bit about different names for heads of government: presidents, kings, queens, prime ministers. They wanted to put "mayor" on that list, and one student asked me if there was a king in Rome. (Not to hear Caesar tell it!)
When lesson time came, I decided before we even read the magazine that we should figure something out about the three branches of government in the hopes of pinning an abstract concept like "Supreme Court" onto something concrete. From prior conversations with these second graders, I knew what interested them most (besides SpongeBob). "Who in here likes sports?" I asked. Everyone in the class raised his or her hand. "Who is on a sports team?" Not every hand this time, but a substantial number. I asked one girl what her grandfather did for her soccer team (again, I knew the answer in advance because of a prior conversation).
"He's our coach," she said.
We went into what a coach does, and then I wrote "Coach" on the board.
"And what do we call the person who decides what happens if the soccer ball goes out of play?"
When the class gave me the answer, I wrote "Referee" on the board.
"And then there must be some group of people who came up with the rules of soccer and who can decide, say, if there should be 20 people out on the field instead of 18." Not knowing the name of this shadowy organization, I put "People who make up rules" on the board.
Then I explained that these were like the branches of our government. The president is like the coach, except less likely to take you personally out for pizza; the referee is like the Supreme Court, and the people who make rules, Congress.
I think they got it, but even if they didn't, at least it was an introduction to the concept, which is what an awful lot of second grade is about.