There's never really any true way to know whether a Saturday Night Live sketch will become an instant classic or quickly fade from memory. But as Will Ferrell taught audiences on April 8, 2000, you can tilt the odds pretty drastically in your favor if you fall back on a Blue Öyster Cult hit, some banging cowbell and a fittingly bizarre Christopher Walken performance. We're talking, of course, about the "More Cowbell" sketch, which imagines the recording session that produced the Blue Öyster Cult classic "(Don't Fear) The Reaper" — specifically the contributions made by cowbell player Gene Frenkle (Ferrell),...