This is your opportunity to see such treasures as the Tower of London Barbary lion skulls, the first maggot ever used as forensic evidence to convict a criminal in court, and a skull of the recently-extinct Chinese river dolphin, which has never been brought out in public before.
Three hundred of the scientists who usually work in the bowels of the museum's many locations, and aren't usually allowed out in public, will be available to answer all your stupid questions. They will presumably been briefed to expect vacant plebs like your author, with the sort of stupid questions members of the public have, about which would win in a fight out of a tiger and a lion, or how bonobo monkeys say hello.
It runs tonight from 4pm until 10pm and entrance is absolutely free. For more, see http://www.nhm.ac.uk/visit-us/whats-on/after-hours-science-uncovered/index.html