MARQUETTE, Mich.— Northern Michigan University will host an intensive series of workshops over a single morning to give high school students an in-depth look into acting and theater. The event is scheduled from 9 a.m. to noon Friday, March 29, in Forest Roberts Theatre.   Featured workshop presenters include NMU theater professors Ansley Valentine, Paul Truckey and Shelley Russell.    Cost is $20 per person and registration is limited. Participants can register by contacting the Forest Roberts Theatre box office at 227-2553, frtbox@gmail.com or by visiting in person. At-the-door registration and payment will be accepted if space permits.    For questions or more information, contact Nikke Nason or Meghan Marquardt at 227-2553.