Spider stretch
This move not only engages the median nerve, but also stretches the palmar fascia (the connective tissue within your palm).
Place your hands in an upside-down prayer position. Keep your fingers and thumbs touching as you spread them apart as wide as possible. Gently push your wrists apart. Press your palms closer together, then widen again. (Imagine a spider doing push-ups in front of a mirror!) Repeat five times.