Viral gene circuits are bounded by many of the same design constraints as electrical circuits (e.g., signal-to-noise ratio) but rapidly mutating viruses, like HIV, evolved unique mechanisms to circumvent these circuitry barriers.  These adaptations are essential to the evolutionary fitness of viruses and offer targets for novel antiviral therapies.  I will describe two viral circuit adaptations, the first in HIV (Weinberger & Weinberger, Cell, 2013) and the second in the human herpesvirus CMV (Teng et al., Cell, 2012), the leading cause of birth defects and transplant rejections.  I will also discuss very recent work on disrupting and exploiting these circuit architectures for new therapies (Dar et al. Science, in press).