The last 7-odd years in my 20 year career, 50 (very smart) people, multiple teams. Long enough to watch it spread through a company, with the attendant disruption, only to be revised away as the realisation set in that, like so many silver bullets, it was only nickel-plated at best.

Now I'm watching as another 'Agile' team pushes 6x4 cards around (at least they've managed to adopt a half-assed electronic version of that). Sadly there's no methodology that'll save them, but that's a different problem.