Every kid who went through the public school system in California remembers doing the mission projects in fourth grade. Hello styrofoam and toothpick renditions of famous pieces of California's history. However, I don't think anyone actually remembers much about the missions other than they had something to do with Native Americans and Christianity.
In a fit of nostalgia (adventure? spontaneity?), I visited San Diego's mission, the Mission San Diego de Alcala. Interestingly, it was the only mission to have been rebuilt due to a past fire. It was rather smaller than I remember the other missions being, but still very mission-y. I probably should have taken a guided tour because just reading the signs wasn't all that informative.
All in all, still a nice way to spend a Saturday afternoon.