Michael, Archiver of Stuff

{t}Target player exiles the top two cards from
their library. Place one of those cards on either
the top or bottom of your library. Place the
other in its owners graveyard. Until your next
end-step, you may spend mana as though it
were mana of any color.
I've yet to collect Urza's Tome volumes 16-19 in their original dwarf-skin binding.
QUICK! TO THE BAZAAR!