Calliope, Muse of Eloquence:  English Words from Classical Mythology

somnambulate

Somnus was the Roman god of sleep. He lived in a quiet valley that was so deep the sun never shone there. The only sound in the valley came from Lethe, the river of forgetfulness and oblivion. Poppies bloomed near the door to his home. Not surprisingly, Somnus spent his days asleep on a soft, dark bed unless someone had an errand for him to run, like bringing news of Cyex's death to Alcyone.

A person who somnambulates is doing what?

sleepwalking
shopping on the Internet
dancing