By Phil Contrino

While it should still be a successful film, Tropic Thunder may not open quite as big as many in the industry predicted it would.

The film grossed $6.5 million on its first day of release and that total falls well beneath the $12.08 million that Pineapple Express was able to bring in last Wednesday. Express went on to gross a slightly underwhelming $23.2 million last weekend, which wasn't good enough to topple The Dark Knight.

While Thunder could certainly pick up today and gain even more momentum heading into the weekend, expectations are being downgraded for the time being.

Moviegoers are now experiencing an onslaught of R-rated comedies since Step Brothers opened with a solid $31 million during the July 25th weekend. In the weeks to come, two more R-rated laughers, Hamlet 2 and College, will try to tap into audiences who prefer their humor to be a little more dirty.