It’s been 25 years since Jim Belushi and Alex Karras teamed up on Saturday Night Live to perform “White Guy Rap,” a hip-hop parody that found them dressed in WASPy golf duds and extolling such upper-class joys as getting a vasectomy and voting GOP. (The sketch is sorely absent from YouTube; can somebody with an old “Best of the Gary Kroeger Years” VHS please get on this?) The sketch was one of the earliest examples of white-rap comedy, a self-explanatory subset of white rap in which Caucasian comedians — or alleged comedians — try their hand at rapping, often in an attempt to either satirize or confirm their own innate honkiness. It’s a joke that’s lasted far longer than anyone would have expected: Witness Gwyneth Paltrow’s recent Kangol-capped appearance on Late Night With Jimmy Fallon, in which she and Jimmy revealed their past career as an eighties rap team. And while white-rap comedy might seem like the ultimate one-note gag, it’s actually evolved over the past three decades in surprising ways. Herewith, a gallery of white-rap comedy’s highs and lows, from Rappin’ Rodney to “Lazy Sunday.” Word. (But white-guy ironically “word.”)