SHEILA’S IMPROV-O-RAMA, Sheila, at Bailiwick Repertory, and The New Show, Aha!, at Bailiwick Repertory. Sheila’s seven-year history and roots in Hyde Park (the revered Compass Players’ spawning ground) are good credentials to have. But its own merits are what distinguish this improv troupe. Chief among them is an intelligent, sophisticated humor rarely relying on pop-culture references, exaggerated dialects, or facile stereotypes: in Sheila’s Improv-o-Rama, an arthritic geezer in a nursing-home gymnasium who gleefully turns handsprings–assisted by two medics–draws laughs from the physical comedy rather than mockery of the would-be athlete.

The Sheila ensemble members are also confident enough to act on their inspirations immediately. In fact their lively pace belies the fully improvised nature of the show, a series of episodes each providing the premise for the next. Even their displays of technical virtuosity–repeating dialogue in reverse or slow motion or making a household word into a “fighting word”–are performed with such agility and focus that we barely recognize these as training exercises. A half dozen songs, likewise composed extempore, are accompanied by two guitarists as closely attuned to each other and to the onstage proceedings as if everyone had been rehearsing for weeks.

The Aha! company dispensed with the improvised portion of their program on the night I attended. But more spontaneity is not what this group needs, judging by its scripted material: these players work very hard to be funny but seem to have given little thought to the plausibility of their premises. For example, the mother of a Waspish bride is portrayed as a standard-issue Jewish matron, while the bride’s boisterous, oafish, where’s-the-bar father doesn’t seem Jewish at all. A few bits do reveal traces of originality: in one, two snobbish gay men find their diet sabotaged by disgruntled lesbians; another is a blues song in which a temporary and a full-time worker both lament the conditions of their employment. But even at its best, The New Show would seem to require an audience as parochial as the people it ridicules.

–Mary Shen Barnidge