The funky keyboard pictured was used on MIT lisp machines, not by the "old unix gurus".
!:$:t is referred to as a Modifier in the bash man page (not a transformation). A complete reference on Event Designators, Word Designators, and Modifiers can be found in the bash man page.
'#' is more universally called the octothope (pointed out by mrwabu on reddit). "Pound Sign" is it's common name in North American. Forgive me for my ignorance, international viewers.
Tim Harper (tim.theenchanter.com) presents a 13 minute tour of some of his favorite bash features that he uses on a daily basis. The font size is tiny, so be sure to watch it in full screen.
