Nobody but you and I is/are/am in the classroom right now.

I would say, "Nobody is in the classroom but you and me."

The grammar book is right. "Nobody" and "no one" take singular verbs.

The phrase "you and I" is object of the preposition (in this case) "but," and has nothing to do with the verb. The prepositional phrase modifies the subject, "nobody."

Personally, I'd use the objective case, "nobody except you and me," but I guess that's a losing battle.

AngliholicAccording to a grammar book here, the answer to the above is "is."

The grammar book is correct. Nobody is. Nevertheless, you will hear

Nobody but you and I are in the classroom right now.

-- probably more often than is.

I myself would use are in conversation, even though I'd answer is

So is the technically correct version

Nobody but you and me is

or

Nobody but you and I is

If Avangi is correct in saying but is a preposition, then shouldn't it be the objective case?

Notice that when Khoff changed the sentence order, she also used the objective case.
Even Frank Sinatra uses it, and he's

Well if my good ol' friend Frank said it, I have no choice but to agree. Cogent reply, Avangi

AvangiEven Frank Sinatra uses it, and he's never wrong:
It's quarter to three, no one in the place except you and me.

What's to say it wasn't the need for a rhyme that dictated the choice?

It's quarter to three,
no one in the place except you and me.

Who knows what the last word in that series w

hey,
here, the sentence "nobody but you is in the classroom right now." is correct because here the subject (the one we are talking about in the sentence) is "nobody" and according to nobody the verb must be "is" as - nobody is. Therefore the sentence is correct with "is" in it. Few more examples - Nobody but you is hurting me. Nobody but you are my best friend.