Friday box office estimates from Boxofficemojo:

1. THE INCREDIBLE HULK: 21 mil
2. THE HAPPENING: 12.8 mil
3. KUNG FU PANDA: 10 mil
4. YOU DON'T MESS WITH THE ZOHAN: 5.4 mil
5. INDIANA JONES AND THE KINGDOM OF THE CRYSTAL SKULL: 3.7 mil

It looks like The Incredible Hulk may make around what the first movie made in 2003 for its opening weekend. The first movie had a horrible drop after the first weekend due to poor word of mouth, so hopefully this one will have better legs.