The last time you attended a light show, it wasn’t what you’d call a healthy experience. Although you do remember thinking you had discovered the meaning of life. Here’s one that might actually enhance your well-being: the photomodulation facial at Nob Hill Spa. It begins with the regular facial stuff: cleansing, extracting, hydrating. Then comes the light show (so to speak) appropriate for your skin type — sensitive, mature, dry, blemished, oily. Light-emitting diodes set to specific spectrums purportedly stimulate cells, increase circulation, promote collagen activity, and restore the skin’s natural cellular activity. (Fret not. It’s safe.) So it won’t help solve any existential crisis. But you will wake the next day with fewer dark circles and firmer, glowing skin. A definite step up in your morning-after memories. Nob Hill Spa, 1075 California Street, between Taylor and Mason Streets (415-345-2888).