"Zodiac," a well-acted, excellently produced and highly compelling drama, played second fiddle at the box office this weekend to a silly movie about guys falling off Harleys.

Snobby commentary on America's pop cultural choices aside, I must say "Zodiac" is a must-see.

Highlights:

* This is a movie about a serial killer that isn't trite, doesn't involve grotesquely sexual scenes (really, no sex at all) AND actually shows very little violence.

* Robert Downey, Jr. puts in a riveting -- and hilarious -- performance as drunken San Francisco Chronicle reporter Paul Avery.

* More excellent performances, from Mark Ruffalo, John Carroll Lynch, and a host of other character actors you KNOW you've seen in a movie before but just can't quite name. Actually, though Jake Gyllenhaal, Anthony Edwards and Chloe Sevigny, three of the main roles, do a great job, I think the best performances come mostly from the guys in the smaller roles. It's a movie based on a true story that you actually can believe.

* One of the creepiest, look-over-your-shoulder scenes in recent movie history; when Robert Graysmith (Gyllenhaal) goes to the home of Bob Vaughn (Charles Fleischer) to gather some information about the case, he confronts his worst fears as he starts to realize Fleischer could be the Zodiac.

* The rather un-Hollywood ending...and I'll leave it at that so as not to spoil it.