To + verb, bare verb or verb + ing in noun phrases

Question

Which one is the correct verb form in the following sentence?

The craziest thing I've ever done is go / to go / going scuba diving in Belize

Some people say that both the to + verb and the ing forms are correct, because you need a noun there and the bare form is a verb; other people say only the to + verb is the correct one here, because the ing form only applies when you reverse the sentence (going scuba diving is yadda yadda) and not when you place the subject in the end.

I know many people would use the bare infinitive to be quicker while speaking, but that just sounds wrong to my ears as it's a verb!

Can you please tell me, once and for all, which is the correct verb form?

Answer 1

As you yourself have pointed out, there is no singular correct sentence ("many people will use").
All of your proposed sentences are understandable, however, the going-ness of it is not necessary since it could only be understood that you went and did something.

#2 sounds usual for your phrasing

#3 sounds a bit awkward, probably because a listener would except to hear "scuba diving" directly instead of "going scuba diving".

However, #4 sounds most usual and normal.

1) The craziest thing I've ever done is go scuba diving in Belize.
2) The craziest thing I've ever done is to go scuba diving in Belize.
3) The craziest thing I've ever done is going scuba diving in Belize.

4) The craziest thing I ever did was scuba diving in Belize.

Answer 2

The craziest thing I've ever done is go / to go / going scuba diving in Belize? as I know " The craziest thing I've ever done is" needs an object, so my answer is " going". we use: S + be + to infinitive means we need to do.