The 13th American College Theater Festival opened last night with a home-grown concoction called "Jeririgg," from Oakland University in Rochester, Mich., an evening that illustrated fully both the advantages and disadvantages of college theater.

"Jeririgg" (which may or may not be a play on "jerry-built")is a pot-pourri of mime, sounds, songs and scenes loosely strung together with aphorisms and energy. Nine players in clown costumes reminiscent of "Godspell" on a stage outfitted with scaffolding and three movable screens manage to create their own daffy world, one that is by turns amusing, poignant or just plain dippy.

"Crazy words and crazy tunes," announces one posterboard, which is a rather insubstantial conceit on which to base even 90 minutes of entertainment. The clown troupe arrives onstage and plays the title song in jolly jug band style, complete with toy piano (literally) string bass, and then proceeds through its set of scenes.

One scene, for example, is called "Looks Are Deceiving." A man fences in samurai fashion; an onlooker is convinced he has killed a third person. She convinces several others, only to find that the man is not dead after all. In "A Little Knowledge Is a Dangerous Thing," a drunken doctor operates on an appendectomy patient, bopping him on the head to put him out instead of waiting for the anesthesia to work, takes out what are clearly his intestines, and ditches the body when the patient dies.

The scenes are linked by interludes in which a character named Patsy proceeds to loose her innocence as well as her security blanket. Like too much in the rest of the show, the Patsy interludes are rather half-baked in concept and don't shore up the spine of the evening.

As mimes, the college players range from excellent to adequate. Too often actions are diffused with too many little movements, rather than the clean, sure lines that mime demands. Sometimes the action is rather sophomorically gross, using breaking wind, nosepicking and stepping in manure to get laughs. At least one of the show's creators seems to have watched a lot of "The Three Stooges."

There is a lot of talent informing this creation, but we are not introduced to individual players by name so it is impossible to single out anyone. That talent has created a stageworld that in some ways resembles that of liberal arts university -- cocooned by group living, freed from other-worldly conventions, able to try on the costumes of different ways of thought, but generally unfocused and sometimes self-consciously precious.