The first "Marvel" movie featuring a female lead.
While filming the sai/sword fight, Jennifer Garner accidentally got her knuckles sliced by Will Yun Lee. She got her knuckles patched up, and when she and Lee resumed, he subsequently sliced her again in the exact same spot.
Jennifer Garner reportedly told a journalist that she felt this movie was terrible, and that she only filmed it because of contractual obligations from Daredevil (2003).
Ben Affleck filmed a cameo reprising his Daredevil role as Matt Murdock but was cut from the final film.