The screwed-up world of Woody Allen finds compelling expression in Writer's Block, two new short plays that opened last night at the Atlantic Theater Company.

Allen does a superb job directing his own plays (a first for him), both of which deal with marriages in a pickle.

The first, Riverside Drive, features an edgy collision between a distraught novelist and a talkative bum.

As excellently played by Paul Reiser, Jim, the novelist, is at first disdainful as Fred the bum accuses him of stealing his life.

But as Fred goes on talking about how he has a Ph.D. from Brown and has been commanded by a '40s Philco radio to burn the ad agency he used to work at, odd things emerge.

Jim's own story gradually emerges, too. He has a wife and twin sons, but has been having an affair. He has summoned the woman to the park to break things off.

But the bum is more than a bum -- he is, in a sense, a projection of Jim. Skipp Sudduth is amazing as Fred, at once a comic cuckoo and a sinisterly convincing presence.

The second play, Old Saybrook, takes place in a big, woodsy living room in that fashionable Connecticut town.

A chic couple is entertaining the wife's sister and her husband when they're interrupted by the people who used to live there.

Welcomed, the couple make themselves at home, at one point unearthing from a hidden spot a diary that will expose affairs and cause havoc.

Here there's a plea for forgiveness as a solution to marital unfaithfulness. I'm not sure I buy it from this source, but Old Saybrook is enormous fun anyway.

The acting is uniformly enjoyable in the mode of high comedy. Bebe Neuwirth and Jay Thomas are the gracious hosts; Heather Burns and Grant Shaud the daffy relatives; Christopher Evan Welch and Clea Lewis the pushy guests.