A lot of us participate in threads around alternate versions of the Beatles, Rolling Stones, Pink Floyd, Beach Boys, etc. - but I don't think I've seen quite so many threads around AH ideas that have to do with genres more associated with African-American artists like soul or funk music. So, just off the top of my head, here's a few:
1. December 12, 1964: (an obvious one) A little bird/sixth sense tells Sam Cooke not to go back to the Hacienda Motel with Elisa Boyer. He's alive and well on December 13.
2. December 10, 1967: (another obvious one) The weather clears up a little bit in Madison, Wisconsin, and Otis Redding's plane manages to land safely.
3. 1956: Jackie Wilson is signed to Atlantic Records rather than Brunswick. Jerry Wexler either produces him himself or assigns a producer to him. Therefore, Jackie's amazing voice is matched with good material and a producer/label who know what the hell they are doing.
4. 1972-ish: Sly Stone gets himself into rehab and gets over his cocaine habit before it wrecks his talent.
I'll see if I can think of some more.