Bad Box Office

The box office numbers for this past weekend (Sep 19-21) were horrible:

1. Lakeview Terrace - $15.6M
2. Burn After Reading - $11.3M
3. My Best Friend's Girl - $8.3M
4. Igor - $8.01M
5. Righteous Kill - $7.7M
6. The Family That Preys - $7.5M
7. The Women - $5.31M
8. Ghost Town - $5.17M
9. The Dark Knight - $2.95M
10 The House Bunny - $2.8M

What happened?