LOS ANGELES — An elite squad of guinea pigs has worked its own brand of magic at the box office, taking the No. 1 spot from Harry Potter.

The 3-D "G-Force" was the top movie at the box office this weekend, opening with $32.2 million, according to studio estimates. The Walt Disney release, with its mixture of live action and computer-generated animation, is a "Mission: Impossible"-style adventure.

Last week's No. 1 film, "Harry Potter and the Half-Blood Prince," came in a close second with an estimated $30 million. That's a 61-percent drop from its opening last weekend.

Estimated ticket sales were:

1. "G-Force," $32.2 million.

2. "Harry Potter and the Half-Blood Prince," $30 million.

3. "The Ugly Truth," $27 million.

4. "Orphan," $12.8 million.

5. "Ice Age: Dawn of the Dinosaurs," $8.2 million.

6. "Transformers: Revenge of the Fallen," $8 million.

7. "The Hangover," $6.5 million.

8. "The Proposal," $6.4 million.

9. "Public Enemies," $4.2 million.

10. "Bruno," $2.7 million.