Remember when summer camp meant hiking, fishing, a little water-safety training and weaving lanyards for the folks back home?

Well, for some campers, the canoes and tennis rackets of summers gone by have been sleekly supplanted by electronic keyboards and dual disc drives.

Welcome to computer camp. Summer of '82.

Now, instead of a few rounds of Ping-Pong or a fast game of kickball, kids can spend their time encoding data programs on computer peripherals or zapping the dot-patterned villain in the electronic version of Cowboys-and-Indians, dubbed simply "Outlaw."

Here in Washington, Atari, maker of the addictive Pac-Man and Space Invaders, picked up the tab for 64 disadvantaged District children to attend computer day camp at the Capital Children's Museum.

For four-week sessions the participants, in two groups of 32 each, camp out in the museum's gray-walled Future Center, programming numbers and letters into pictures and music, while visions of extraterrestrials dance in their heads.

For 13-year-old Anthony Jones, this summer's goal was not a swimming badge or a color war trophy, but a program that would allow his rocket ship to pelt the enemy with a crimson laser blast.

Hunched over the keyboard, gazing into his terminal, Jones warily hunt-and-pecked the letters: GR: GO TO 10, -20, and, along with his friend Johnny Crestwell, 12, crossed his fingers, held his breath and hoped the command would work.

"Please come out right this time," Jones implored the computer.

It didn't. Instead, the computer answered back, "WHAT'S THIS!!!" and impassively left them at square one with a rocket ship incorrectly split by a crossed laser beam.

"Why'd you push the run button? I told you not to push run!" sighed an exasperated Crestwell. "So what do we do now?"

"I know what happened," Jones assured him; "we forgot the pause."

Pause? Run? GR: GO TO 10,-20? All part of the computer lingo the campers managed to pick in the space of just a few days.

"They really don't need us," said John Brown, head teacher at the camp. "They know what they're working on. We just give them their discs and they take it from there."

With his program disc loaded in its dual disc drive, 11-year-old Douglas Christiano set out to take on the laborious task of encoding the entire "Star Wars" theme--note by note, entry by painstaking entry.

How do you get a computer to play music, you ask?

In answer, Douglas pulls out a wad of graph paper and music sheets scrawled with numbers, letters and marginal scribblings that would baffle Mozart.

He then rambles off a string of instructions that call to mind the most vexing of algebraic formulae in describing the conversion of musical notes into numbers and symbols the computer can understand.

"Q equals 40 and T is one-third of Q, which is a quarter-note," he explains. "H is a half-note and equals two Q's . . ."

It took him half an hour to finish the first bar of the song, an entire day to finish the rest--and the play-back (which wasn't too bad in video-phonic sound) still had its share of off-notes and other understandable kinks.

"I'll go back and fix them tomorrow," said Douglas after listening to the finished product--kinks and all. "I've had it for today."

Stumped at the neighboring terminal, Felicia Bloodsaw, 13, was furiously trying to figure out the correct command for drawing water under the otherwise drydocked vessel she had depicted on her screen.

"Don't you remember how to make water?" asked her friend Hope Crudlup, peering over her shoulder. The frustrated fledgling computer programmer was by this time drawing not water but a small crowd of curious fellow campers. "She's trying to make water again," she told them.

"See if you can make waves this time," Crudlup suggested.

"I can't even make water--let alone waves!" said Bloodsaw, still fidgeting with the keyboard. "Why don't you go draw or something."

Building fires and tying knots are kid stuff compared with encoding and decoding. But composer Douglas is not intimidated by the future.

"The computer's really dumb until you put things into it," he said. "It doesn't even know it's a computer. You have to teach it everything."

Just like parents.

"Nobody understands in my family," laments George Scarborough, 12. "I could talk to my mother for an hour about computers and she still won't get it."