Estimated ticket sales for April 18-20. Dollar figures in the millions. There are no ties; numbers are rounded off.

1. The Forbidden Kingdom  $21.4
Total: $21.4, one week
Locations: 3,151

2. Forgetting Sarah Marshall $17.7
Total: $17.7, one week
Locations: 2,798

3. Prom Night  $8.7
Total: $32.1, two weeks
Locations: 2,700

4. 88 Minutes  $7
Total: $7, one week
Locations: 2,168

5. Nim's Island  $5.7
Total: $32.9, three weeks
Locations: 3,277

6. 21 $5.5
Total: $70, four weeks
Locations: 2,903

7. Street Kings  $4.2
Total: $20.1, two weeks
Locations: 2,469

8. Horton Hears a Who!  $3.5
Total: $144.4, six weeks
Locations: 2,670

9. Leatherheads $3
Total: $26.6, three weeks
Locations: 2,798

10. Expelled: No Intelligence Allowed $3
Total: $3, one week
Locations: 1,052

SOURCE: Exhibitor Relations Co. Inc.