What's happening: A month-long trial has begun in a California federal court where Elon Musk is suing OpenAI CEO Sam Altman and the company.

Musk's core claim: Musk argues Altman swindled him out of millions and betrayed OpenAI's original non-profit mission by turning it into a for-profit entity, largely benefiting Microsoft.

OpenAI's defence: The company says Musk is motivated by jealousy and regret after leaving OpenAI, and that he agreed a for-profit model was needed but wanted total control. A 2018 email from Musk is cited where he threatened to stop funding.

Key stakes: The case could affect the race to develop Artificial General Intelligence (AGI). A win for Musk could hobble a major competitor, xAI, his own AI company.

Public feud: The animosity has been very public, with Musk calling Altman "Scam Altman" and a rejected $97.4bn takeover bid for OpenAI leading to personal online jabs.

Notable details: Both men and other tech leaders like Microsoft's Satya Nadella will testify. The judge has warned their wealth and celebrity won't earn them special treatment, and some personal details (like Musk's past use of ketamine) have been barred from court.

I hope this summary is helpful. Let me know if you would like any part of it clarified.

Why Sam Altman and his former hero Elon Musk are taking their toxic feud to court