Grok, an AI chatbot system from Elon Musk's xAI company, was rolled out to U.S. users of the X social media platform in December. Designed to rival market-leading AI systems like those from Google and, especially, OpenAI, the chatbot distinguishes itself from its peers by incorporating humor and sarcastic tones from the AI computers in the famous Hitchhiker's Guide to the Galaxy books. Last week Musk, who owns both X and xAI, announced Grok would be made open source, and that's now happened: coders around the world can peer into the workings of Grok and even use it to drive their own AI efforts.