Night at the Museum: Battle of the Smithsonian widened its first place lead by grossing $20 million on Saturday, according to box-office estimates. This brings its three-day weekend estimate to $53.5 million. By comparison, the original Night at the Museum opened to a three-day weekend tally of $30.4 million in December 2006, and then showed incredible stamina during the following months. As for Terminator Salvation, the future may be looking bleak. Salvation grossed $14.8 million on Saturday — a small drop from its estimated Friday harvest of $15 million. Nearly all of the movies in the Top 10 saw Friday-to-Saturday boosts of at least 20%, so the fact that Salvation’s numbers are actually dropping is cause for concern. Salvation is on track for a three-day weekend total of $43 million. The last Terminator movie, Terminator 3: Rise of the Machines, opened to $44 million during Independence Day weekend in 2003. Saturday’s figures are below, and check back here on Monday for a full four-day holiday weekend recap.

1. Night at the Museum: Battle of the Smithsonian — $20 mil
2. Terminator Salvation — $14.8 mil
3. Star Trek — $8.4 mil
4. Angels and Demons — $8.1 mil
5. Dance Flick — $3.9 mil

Source: EW