Two new shows have been added to the Sticky & Sweet Tour US leg.
Tickets for the Madonna concerts in Las Vegas and Denver sold like hot cakes today and a second show has been added to each venue - filling the gap between the stop in Nevada and the one in Colorado that are now separated by one day only:

November 08, 2008: MGM Grand, Las Vegas
November 09, 2008: MGM Grand, Las Vegas - on sale soon
November 11, 2008: Pepsi Center, Denver
November 12, 2008: Pepsi Center, Denver - on sale soon

Source: Madonna Tribe