Rosetta Code provides improv theatre performers with artificial intelligence (AI)-based technology to perform shows understandable across many different languages. We combine natural language processing and language translation tools to enable improvisers to communicate with each other while being understood---or comically misunderstood---by multilingual audiences. We describe the technology underlying Rosetta Code, detailing the machine translation, speech recognition, and text generation subsystems. We then describe scene structures which feature the system in performances in multilingual shows ($9$ languages). We provide evaluative feedback from performers, audiences, and critics.From this feedback, we draw analogies between surrealism, absurdism, and multilingual AI improv. Rosetta Code creates a new form of language-based absurdist improv. The performance remains ephemeral and performers of different languages can express themselves and their culture while accommodating the linguistic diversity of audiences.