"Oil & Water," the San Francisco Mime Troupe's 54th season offering, won't likely go down as the group's best. Still, as are all the free shows presented by The City's beloved and venerable political comedy troupe, it's fun, educational and community-minded — hard things to knock.

Due to funding difficulties, the show, which opened in Dolores Park on sunny Independence Day, is streamlined from previous presentations. A team of just four versatile actors — Rotimi Agbabiaka, Velina Brown, Hugo E Carbajal and Lisa Hori-Garcia — handle all of the roles in the two connected one-acts, and the band includes just two people: Aharon Wheels Bolsta and Pat Moran, who wrote and directed the music (and co-wrote the script).

The world's precarious environmental situation is the theme of both: In "Deal With the Devil," the U.S. president, somewhat reminiscent of Barack Obama (Agbabiaka), finds himself in a pickle about giving a speech on the topic of the massive Keystone Pipeline. In "Crude Intentions," a young woman, Tomasa (Hori-Garcia), who has sensitive documentary film footage about Chevron polluting the Amazon in Ecuador, is pressured to give it up.

Spot-on, mostly-in-San Francisco details (Tomasa and her sweetheart Gracie serve organic nouvelle California-Latin American fare at their cafe in the Mission district), clever jokes ("Remember when this used to come out of faucets?" the president saus upon being given a bottle of water), and crooked politicians and greedy corporate executives, ripe for audience boos, round out the fun.

The best musical number has libertarian billionaire David Koch and a Chevron bigwig rapping "We be runnin' this world" with verses like: "You file lawsuits, but they don't stress us / We subpoena enemy IP addresses / We claim conspiracy, they all out to get us / We make taxpayers clean up our messes" and "If you wanna move mountains and wanna move nations, start some PACs and some family foundations / Send PBS and NPR big fat donations / Then the experts speak your views on every station."

Of course, it wouldn't be a Mime Troupe show if the left-wing truth didn't prevail, and so both sagas end on a hopeful, upbeat note — one that's reflected in program notes, which are packed with online resources for finding more information about the issues covered in the show and ways to combat climate change.