Here’s one way to slice the travel-entertainment budget — join your local science center. Pacific Northwest and B.C. families have three stellar museums in Portland, Seattle and Vancouver to choose from, and even out-of-town visitors can get in on the fun. If you’re a member of your local science museum — in the U.S. or Canada — check to see whether the museum is part of the ASTC Passport Program. Passport Program members receive free reciprocal admission to other ASTC museums. So if your family’s members of OMSI, you get into the Pacific Science Center for free. If you’re members of Science World, you get into OMSI for free. See? You’ll…