Not to pick nits, but wasn't Guy Fawkes planning on blowing up parliament (not the Tower)?
"A penny for the old guy" comes from the tradition of Englanders going door to door on Guy Fawkes Day. It's kind of the equivalent of trick or treating, only the house dwellers give out pennies (or so I've heard).
"A penny for the old guy" (or whatever the actual line is) is best known to Americans (and high school students, perhaps the most) from TS Ellio's poem "The Hollow Men". Before the body of the poem is a two line intro, one borrowing from the first line of Conrad's "Heart of Darkness" (Kurtz is dead) and the other from Guy Fawkes Day. Oddly enough, the poem is the same poem Marlon Brando recites in "Apocalypse Now". Oh, and Brando's character's name was Kurtz.
http://www.d.umn.edu/cla/faculty/tbacig/hm...anth/eliot.html