I have just discovered that there is, not only, a name for the combination of the interrogative point (question mark) and the exclamation point but also a typographical symbol. The Interrobang is this combination and can be represented as '?!', '!?' or '‽'. In the past, I have used '?!' because I felt that it provided an appropriate representation of questioning and excited emphasis; I prefer the exclamation after as it is the question that is being emphasized, not the emphasis being questioned. Now, however, the single typographical character provides me the opportunity to concisely express, in writing, simultaneous inquiry and surprise.
Unfortunately, although available in Unicode, many fonts do not have '‽' and there is no easy character combination that will lead to it.
In the world of HTML, you can often get away with ‽