A combination of the words monotone and drone on, monodrone describes a way of telling a story that threatens to put the listener to sleep or encourages her to attempt strangulation of the speaker. A story told in monodrone has no narrative arc, no punchline, no interesting tidbit details, and seemingly no end - it is simply incessant noise. Monodrone can also be used to describe the speaking style of some lecturers - no amount of caffeine is sufficient to keep the student alert and attentive.
His story had no narrative arc, no punchline, no interesting tidbit details, and seemingly no end - completely monodrone. He went on and on... and on, and still nothing happened. He didn't make me laugh, didn't make me think. His incessant noise was just interminable and I started fantasizing about jumping across the table to strangle him. But I feel bad, because he is actually a really nice person.