Wouldn’t it be great if there was punctuation that both elicited excitement and disbelief? Today, people use a combination of a question mark and exclamation point (“?!”) to express this in informal writing, but back in the early 1960s, the interrobang (“‽”) had its moment of fame thanks to advertising executive Martin Speckter. In 1962 Speckter introduced the interrobang as a “typographically eloquent way in which to end a statement that expresses excited disbelief, asks a question in an excited manner, or proposes a rhetorical question.” Due to its popularity, some typewriters included an interrobang key.
The interrobang was short-lived, however. By the time the late 1960s rolled around, people had reverted to using the combination of question mark and exclamation point. Nevertheless, if you are interested in using an interrobang, your word processing program should still have it. For example, in Microsoft Word, type the letters 203d, then immediately hit the key combination Alt + x. That should convert 203d to an interrobang. While only certain fonts can display this unique punctuation, Word should convert the font to the closest matching font you are using that supports the interrobang.
If you do use an interrobang in your writing, have fun with it, but be sure to keep it to informal writing only.