Curly Brackets
These are indispensable in programming (where they usually indicate a block of looping code) and emoticons (where they usually indicate a mustache) but I'm not entirely clear on where they'd show up in normal written text. Parenthetical statements on wedding invitations, perhaps. Or citations of illuminated manuscripts. B

Tilde
I know what this is for, I'm just surprised that it gets its own key and the noble umlaut doesn't. It's not even very useful for ASCII art, because font designers can't seem to agree whether it belongs at the top of the line or in the middle. I suggest we decide that by itself it's pronounced as a nasal "gn," such as the noise made by an annoyed Curly or an aroused Squiggy. C-

Commercial A
Okay, incredibly important point here: To anyone who's spent enough time on the Internet to get cold chills when receiving mail with the subject "Very Funny! Read!", the commercial a is pronounced "at." So those clever motherfuckers among you who come up with spelling like "One-D@y Am@zing De@l S@le," are subjecting us to a mental pronunciation that comes out like "One Datee Amatzing Deattle Sattle." Stop it. B

Pound Sign
The name of this has only recently been standardized, and many still refer to it as a hash symbol, an octothorp, or a "tic-tac-toe board for little tiny miniature people." I don't mind the name, but on the other hand I've never seen it used to actually indicate pounds either in the scale sense or the quid sense. ("My quid sense is tingling!") I like to think of it as coming from the practice of pounding the phone buttons after going through one too many labyrinthine voice mail systems, but that's probably due to my fanciful nature. B

Backslash
I have, at various points in my life, been in the position to use both some form of DOS and some form of UNIX. Those of you who have no duck-strangling idea what I'm talking about, just smile and nod. The only point here is that DOS uses backslashes a lot and UNIX uses forward slashes a lot and the effect of using both is somewhat like having Darth Vader for homeroom and Yoda for first period. Many say that DOS is the dark side, but actually UNIX is more like the dark side: It's less likely to find the one way to destroy your incredibly powerful machine, and more likely to make upper management choke. C-