Neither stifling heat, an overcrowded gymnasium nor a total disdain for that phase of the game called defense dims the enthusisam of the thousands of summer league basketball addicts who never seem to get enough of the city's most popular game.

The best summer competition in Washington is found in the 10-team Urban Coalition Summer Basketball League that started play Friday night. Games continue today at 2 and 4 p.m. and during the next seven weekends, all at Dunbar High School.

Almost every game features NBA stars like Adrian Dantley, Truck Robinson, Gus Williams, Robert Reid and Moses Malone. The Urban Coalition also offers an early peek at Washington Bullet draftees.

This year fans can catch a glimpse of the up-and-coming area college stars. This year's top attraction, Georgetown's 7-foot center, Patrick Ewing, will "probably play a few games," according to his coach, John Thompson. Even Virginia's 7-4 all-America center Ralph Sampson may make an appearance or two.

There is no way to tell who will show up for the games. The players are not compensated. Most of the pros participate to keep their games sharp.

"If you don't get there early, you won't get in," said Jim Wiggins, the league director. "There isn't an adult league on a par with this one anywhere in the country. We will have great players and the competition is always good. This is a dynamite league."

There are several other summer leagues in the area that offer outstanding competition, particularly the five high school leagues. The Urban Coalition sponsors a high school league on weekends and a women's league each Thursday, also at Dunbar.

The oldest, most competitive and most popular prep league is the Jelleff League, which plays its games all the Boys and Girls Club at Wisconsin and S streets NW. A total of 24 balanced teams from the metropolitan area are split into two divisions. At times, there are as many college scouts in attendance as there are fans. The top high school players usually play in the league and the recruiters begin their chases early.

"I'll be a regular visitor at the summer league games," said GW's new head coach, Gerry Gimelstob. "My priority is to recruit local kids. You have to do that to have a good program."