Spring Fling concert announcement takes down the Pipe Dream website

Screenshot of Pipe Dream's Google Analytics

It took 90 active visitors to bring the Pipe Dream site to a screeching halt. The site crashed yesterday afternoon because of a traffic spike to an article announcing that Passion Pit will headline the 2012 Spring Fling concert.

Now it’s time to make sure this doesn’t happen again. We already use WP Super Cache and minimize our CSS/JS files. Does anyone have any suggestions?