I was hoping that M. Night Shyamalan's new movie, The Happening, was going to be a return to his early form. I wasn't a huge fan of his early movies but they were decent. Alas, the early reviews for The Happening are in and they are baaaaaad. As it stands now, the movie has a 16% rating on Rotten Tomatoes. Those are Gigli numbers.
One interesting "spoiler" from the early reviews is that a plant toxin is responsible for the strange illness that befalls people. Shyamalan is quoted as saying that the movie is inspired by the idea that "plants can fight back" against humanity.
The idea of killer plants is not a new one. There is a sci-fi book with a cult following called Day of the Triffids in which killer plants take over humanity. Judging from the reviews of The Happening, you're probably better off sticking with the triffids.
If you insist on entertaining yourself with something called "The Happening" listen to the Pixies song, it has a sci-fi subject matter and only lasts 4 minutes instead of 90.