Strange. Very, very strange. There was no discernible plot, but the effects were good, and the drug taking was truly outrageous - the first scene in the car was hilarious. And I found the scenes in the flooded hotel room very surreal.
I'd be interested to know how true to life the effects of the drugs were.
EDIT: Sleep Hollow is an... interesting film. Some of the acting is very shaky, but Christopher Walken makes up for it with has badass Headless Horseman.