Gone are the days when insomnia meant a lonely game of solitaire at the kitchen table, or a 3 a.m. conversation with the cat. Some of Washington's late-night attractions are almost worth setting the alarm for.

Middle-of-the-night movies abound, from classy American Film Institute retrospectives (this Friday and next at midnight, it's a Nicholas Roeg program) to the Biograph's X-rated "Debbie Does Dallas," Fridays and Saturdays at 12:15 p.m. Another fixture, "The Rocky Horror Picture Show," draws legions Fridays and Saturdays at 12:15 a.m. at the Key and Key College Park. For other midnight (or later) shows, check the Avalon, Cerberus, assorted Circles, Janus, Jenifer or Ontario. And watch the paper for the Penn and Town's occasional midnight-to-6 shows.

If it's exercise you're after, and jogging through deserted streets somehow doesn't sound like fun, there's bowling. Nick Rinaldi Lanes are open 24 hours at two locations: 6322 Kenilworth Avenue, Riverdale (864-5490), and 2945 South Glebe Road, Arlington (684-5800), Or practice your backhand, with no court lines for a change. Starting November 1, the Arlington Y Tennis and Squash Club (1122 Kirkwood Road, 522-1700) will be open 24 hours for indoor tennis (through October it closes at 1 a.m.).

Fishing, of course, is great during the wee hours, especially if you like smallmouth bass. They're plentiful in the Potomac north of Little Falls, and should be through October. And there are rockfish lurking in the Chesapeake under the Bay Bridge at night, for those with decent boats -- and experience, cautions The Post's outdoorsman.

If none of these appeals, try looking a little farther afield -- at Baltimore Rent-a-tour's popular "Insomniac Tours," offered every few weeks from 1:30 a.m. to dawn. Charm City could take on a whole new aura by moonlight. Routes vary, but favorite spots include Edgar Allen Poe's gravesite, the wholesale fish market, the Baltimore Sun newspaper offices and Fort McHenry. It's also a great way to meet other insomniacs tours have drawn as many as 90 people. Next scheduled tours are October 7, October 27 (come in Halloween costume) and November 18, and reservations are required. Call 301/653-2998 or write Baltimore Rent-a-Tour, 3418 Phillips Drive, 21208. The $25 fee includes breakfast.

Which brings us to food. Here are some restaurants that cater to the nighthawk trade -- a couple of old favorites, plus some new arrivals you may not have heard of. Unless noted, all are open 24 hours;