When my son asked me to join him on a weekend trip, I knew I’d enjoy spending time with him. What I didn’t expect was one of the best nights of live theater I’ve ever experienced.  My son and I took a trip from Houston to Dallas over the weekend mainly to get out of town for a couple of days, do some shopping, and meet up with some of his friends. My job was to book the hotel and, strangely, pick up a pair of tickets for “Shrek: The Musical” at the Firehouse Theatre. When I asked my son why the play, his answer was simple: “Dominic’s in the…