Proving that farcical family vacations are more enticing than gymnastics, spelling bees, and historical plane crashes, Sony's "RV" landed atop the weekend box office tally by grossing an estimated $16.4 million from over 3,600 theaters. Because nothing says "box office hit" like a good septic tank gag.

Debuting in second place (and 1,800 theaters) was Universal's lauded and controversial "United 93," which managed about $11.6 million in its opening frame, while Disney's gymnastics flick "Stick It" was a close third, grossing approximately $11.2 million from just over 2,000 theaters.

Fourth and fifth place went to a pair of horror-related hangers-on: Sony's "Silent Hill" added another $9.3 million to its $34.2 million total, and Dimension's "Scary Movie 4" yanked another $7.8 million out of moviegoers' pockets, giving it a grand total of $78.1 million.

Lionsgate's "Akeelah and the Bee" debuted to relatively meager numbers by pulling in only $6.2 million from 2,200 theaters.

The summer movie officially kicks off next weekend with the arrival of Paramount's "Mission: Impossible III," New Line's family flick "Hoot," and Freestyle's fact-based chiller "An American Haunting."

For a closer peek at the weekend numbers, click on over to the Rotten Tomatoes Box Office Page.