In "The Hot and Cold Running Circus" there are jugglers, clowns, magicians, musicians, fire-eaters and mimes, adding up to a cast of two.

The two are Jill Klein and J. W. Rone, who hail from Berkeley Springs, W. Va., and do just about all the things they do very smartly. They are particularly nimble jugglers. Last night's performance at the Source Theatre included a wonderful routine in which they kept circling around each other, snatching juggling pins and hats back and forth, and never -- well, hardly ever -- missing a beat.

Clearly, these two possess a mother lode of talent, which they have polished to a high luster. But they are much less skillful about introducing their various routines and tying them together. They have built stage personas for themselves that seem labored and unoriginal, and in these personas -- he's called "Kilo 2.26" and she "Essa Geetle" -- they continually berate each other over contrived and tedious mishaps. Inspired (if that's the right word) by "Saturday Night Live," performers who wish to amuse seem increasingly prone these days to interrupt their acts and apologize for it, sometimes at such length that the act itself is never heard from.

On the evidence of last night's performance, however, "The Hot and Cold Running Circus" would be a good bet for overheated kids in search of summer entertainment. Unfortunately, the show was a one-day event in the Source Theatre's Washington Theatre Festival.