As someone who has had a longtime interest in the events surrounding the Cambrian Explosion, I found this to be rather interesting:

2 explosive evolutionary events shaped early history of multicellular life

Blacksburg, Va., January 4, 2008 -- Scientists have known for some time that most major groups of complex animals appeared in the fossils record during the Cambrian Explosion, a seemingly rapid evolutionary event that occurred 542 million years ago. Now Virginia Tech paleontologists, using rigorous analytical methods, have identified another explosive evolutionary event that occurred about 33 million years earlier among macroscopic life forms unrelated to the Cambrian animals. They dubbed this earlier event the "Avalon Explosion."