They both contain locked up loonies!
Because they are Eh-theists.
Sorry, eh.
to get to the other side.
Insecure.
an Envelope EDIT: My deepest Canadian apologies to those who are calling this a riddle. I always took it as a cheesy joke
A: None. Each lightbulb contains the means of its own revolution.
Ginger snaps
DollarAMA. *Only Canadians will get it, sorry.