We show that candidate contact binary asteroids can be efficiently identified from sparsely sampled photometry taken at phase angles α > 60°. At high phase angle, close/contact binary systems produce distinctive light curves that spend most of the time at maximum or minimum (typically >1 mag apart) brightness with relatively fast transitions between the two. This means that a few (approximately five) sparse observations will suffice to measure the large range of variation and to identify candidate contact binary systems. This finding can be used in the context of all-sky surveys to constrain the fraction of contact binary near-Earth objects. High phase angle light-curve data can also reveal the absolute sense of the spin.