Can I include other as a choice in a drop-down box and then give a space to type in the choice.

You will not be able to do this with a plain DropDown field at least not without utilizing conditions and an extra field that would allow you to do this.

On the other hand, you would be able to do this withing the dropdown and with style if you use our widget: User Contributed Dropdown

This will allow you to add your options, but also to have people filling out the jotform add the option for themselves as well.

Do let us now if that would work for you.