A sexually desireable woman chosen to join the ticket of a much older, desperate politician in a last ditch attempt to gain some popularity. A "Hail Mary" pass.
Much like the well know "Milf" and "Gilf", Vpilf is 'Vice President I'd Like (to) Fuck'. Used to describe McCain's new eye candy Vice President, Sarah Palin. Yet, it is debated weather to call her "Milf" or "Vpilf" because she is also a mother and "Milf" is much more commonly used. Though more examples of Vpilf can come up in the future, Sarah Palin in the first real example of this term.