This is also the solution to the old "putting a smiley emoticon in a parenthesised piece of text". "(What a good idea :)" evidently needs a second parenthesis.

This is also the solution to the old "putting a smiley emoticon in a parenthesised piece of text". "(What a good idea :)" evidently needs a second parenthesis. "(What a good idea :))" looks weird and is ambiguous. "(What a good idea :\))" unambiguous: the non-functional parenthesis is escaped.