'Guardians' on top as North America box office slumps

Yahoo!7 News'Guardians' on top as North America box office slumpsYahoo!7 NewsLos Angeles (AFP) - Science-fiction superhero flick "Guardians of the Galaxy" was on course to claim top spot at the North American box office this weekend as the worst summer blockbuster season in nearly a decade limps to a close. The critically ...