OH! [Open House] San Diego, which gave visitors the chance to visit 47 diverse buildings. Completely free and mostly self-guided--so fun! I only made it to two places...the first is the San Diego Opera Scenery Shop, where they construct opera sets and store props.
Then I went to the Banker's Hill area of SD to see the interior of the First Church of Christ, Scientist, designed in 1910 by Irving Gill, perhaps San Diego's most famous architect. The church was hideously "remodeled" and "modernized" in the 1950s, and it has since been restored to its former appearance.