Amazon's current Blu-ray Boxed Set of the Week is for
Night at the Museum Collection (comprised of
Night at the Museum and
Night at the Museum: Battle of the Smithsonian), which can now be had for $18.99 (53% off MSRP, or $9.5 per movie). This is the cheapest this box set has been. This offer is valid through December 11.
Thanks to forum member "shinseiromeo."