So good, I watched this in two different years. This tightly written and performed episode could easily have been a full-length movie. The convoluted, middle-of-the-night, sleep-deprived, drunken plot is highly inventive, the comedy all works, and there's a very touching moment toward the end. The frustrating aspects of this episode are that thing that happens to us all sometimes, where we know what's real and what's not, but nobody believes us; and there's something tugging at the back of our mind that we can't put a finger on, and we feel stuck: instant viewer identification with the Monk character.
With wonderful performances by uncredited Donal Logue as Gulliver the bar grifter ("Gully"); and by Terri Hoyos as Maria Cordova, the object of Monk's obsession in this ep, who is outstanding in the ending. Also with Jane Galloway Heitz as Essie the grumpy cab dispatcher, and Marcus Folmar as the helpful newspaper delivery man.
If you didn't see this when it originally aired--or even if you did--be sure to catch this on Hulu. There are several very good series on Hulu that were cut from TV for reasons that had nothing to do with how good they were, and I'm very happy that I can find them here.