If you ever have a spare week of your life to lose, you can track the fall-out from 1969's 'Paul is Dead!' conspiracy theory across the internet. There's a particularly entertaining (and apparently endless) series of Youtube videos proving that Mr McCartney was killed in that 1966 car crash, and replaced by a not-quite-near-enough lookalike.
Elsewhere on the net, you'll find massive websites devoted to 'Faul', the fake Paul, and his adventures since 1966. When it comes to conspiracy theories, I'd rather start with something more serious. I've wasted plenty of time since the early 70s trailing through volumes devoted to the JFK assassination, and long ago I decided that the journey was more fun than finding out who actually did it. No answer to the mystery could ever be satisfying enough to make all that reading worthwhile, so it was better not to know.
Back to the point. About twenty years ago, I discovered that issue 222 of Batman comic was devoted to a twist on the 'Paul is Dead!' tale, presumably in a desperate attempt to make Bat'n'Robin seem vaguely hip. (Instead of which, Dick Grayson and his 1970 college chums look as if they've stepped out of a 1962 Frankie Avalon beach movie.) The cover is enticing, and ever since then I've been distantly keen to read the whole comic - preferably without paying $40 for a copy.