Hey Kids: Your on vacation!

Lois writes:

I don’t know where this school is, but I wouldn’t bother going back after vacation, if I were a student who wanted to learn anything about grammar, homophones and apostrophes, at least. I found the sign in a file of photos e-mailed to me by my ever-alert sister, who shares the gene for ferreting out apostrophe and other abuses in the English language.