The OffCast Boys, Will and Jonathan, talk to rising star Mike Bartlett about his debut at the National's Olivier Theatre; present their first field report with a rain-soaked review of Latitude; offer their top tips on making the most of summer festivals in London; review auspicious debut plays For Once at the Hampstead and Mirror Teeth at the Finborough; and devise as many puns as possible for the transfer of Mamma Mia to Shanghai...(it's painful! Ed)