The first thing to pop up was Wikipedia's entry for 'Existential Crisis'. Other options included: a gift guide to "help people take their minds off what comes along with that age", the blog of some lady who'd slunk off to India at 30 to find herself, and a self-help book and article called, respectively, Making Choices, Finding Meaning, and Turning 30, or How I Learned to Stop Worrying and Start Loving.