“H2O” is the delightful Nickelodeon series about three teenage girls who gain special powers after a visit to a mysterious island. And I have copies of the whole first season to give away, with a special bonus — a 90-minute feature film version. Send me an email at email@example.com with H2O in the subject line and tell me what superpower you would most like to have. Don’t forget your address! (US addresses only.) I’ll pick the winners at random on March 12. Good luck!