They are still patching some bulletholes, but the fires have been extinguished and the floodwaters drained. The California Institute of Technology has survived another annual spring rite, transforming the ordinary college prank by quantum leaps into a proving ground for American creativity.

To advance the frontiers of knowledge, some of America's finest young scientific minds surprised their teachers and administrators this week with the following:

A dormitory room filled with water, plus two undergraduates floating and shivering as they waited, honor-bound, for an hour before attempting to retrieve an alcoholic reward hidden in the murkey depths.

A room door blown off its hinges by a chemical reaction gone awry, igniting a garbage can full of combustible material and forcing emergency fire measures.

A ruse of questionable legality which led ground controllers to call back a light plane bearing a Cal Tech senior attempting a daring escape from his undergraduate pursuers.

This surprise attack on university decorum, costing over the years thousands of dollars in damage and untold hours of class time, happens every May on this grassy, tree-lined campus. Seniors suddenly disappear, the remaining undergraduates try in the most bizzare fashion to break into their rooms and university administrators see it all as a possible key to the unquestioned superiority of American technology:

"It is a lot like science is," said Cal Tech news bureau director Dennis Meredith. "The problems are going to come out of the blue and off the wall. They are going to have to know how to improvise."

Americans like to think of scientists as eccentric, so Cal Tech has embraced the idea with a vengeance and created a tradition of pranksterism going back decades. Some of the most bizarre have already become cliches. During one year's version of "senior ditch day," which is what the students call the annual spring event, some undergraduates broke into a senior's room and were dissatisfied with the food and liquor that had been left for them. They disassembled the senior's Porsche, which he had unwisely left in the parking lot. When he returned in the evening he found the car reassembled -- in his room, with the motor running. The stunt has been repeated so often it now is considered passe.

Cal Tech's history of pranks isn't confined to the month of May. Budding nuclear physicists here reminisce about the great Rose Bowl hoax, in which Cal Tech commandos switched 2,300 card stunt instructions to be used by the University of Washington cheering section at halftime. The Washington director watched aghast as his signal to spell out "Washington" instead produced the huge letters for "Cal Tech." Instead of a Washington husky, a Cal Tech beaver then materialized and the message "buy bonds" came out "Buy blondes."

Freshman Scott Gordon, a long-haired biochemistry major, sees pranks as a way to relieve some of the pressures of study at one of the most competitive and distinguished scientific institutions in the world. Cal Tech, he said, "is sometimes like trying to drink from a fire hose."

Under the rules, mostly unwritten, seniors secretly pick a day in May and must be off campus by 8 a.m. or risk being chained to a tree, as one reportedly was Monday. They leave behind "stacks," intricate locks and puzzles which must be solved before their rooms can be entered.

Monday's "stacks" included computer programs, .28-caliber bullets to be fired through preselected holes, the mixing of certain chemicals (which misfired) and dozens of others. Many involved searches for clues hidden throughout the university.

One year a clue was wedged in a crack in the exterior wall five stories up on the outside of the nine-story Milliken Library. The dean of student affairs could be seen praying as an intrepid undergraduate rappelled down the side of the building to retrieve the piece of paper.

Ted Weverka, a 20-year-old sophomore, had been up all night Sunday working on a physics lab assignment when early morning scurrying in the halls told him the seniors were sneaking away.He and some friends solved one "stack" based in identifying rock types. One clue was a book by Nobel laureate physicist and Cal Tech professor Richard Feynman, so Weverka climbed 20 feet up the side of his dormitory to an old bas relief showing Copernicus, Newton and other scientific greats greeting God -- labeled "Feynman" by some unknown student. On top of the head of the God/physicist was the key to a senior's room.

One senior, a pilot, said he still had his room key and dared anyone to catch him. A team of students rushed to the El Monte airport, too late to prevent his takeoff, but invented a story that persuaded flight controllers to order him back. His pursuers grabbed him and got his key.

Senior Kelvin Wagner, 21, an applied physics major, left what he thought was a fairly simple "stack."

"If they poured liquid nitrogen on this lens it would close a relay to an 120 volt AC charge which would drop a large weight which would in turn pull out a nail to unlock the door," Wagner said.

As he spoke, university housekeeping supervisor Ivan Zwelling appeared on his annual survey of "ditch day" damage. Zwelling seemed amused by the week's events and said that students eventually repair or pay for all damage.