When Veterans Affairs won’t treat Grandpa’s ailment, “The Simpsons” (7 p.m., Fox, TV-PG) take a health vacation to Havana.

Now in its 28th season, the animated sitcom continues to combine topical humor, obscure and at times even academic references with silly slapstick. It remains one of the few series that can reach both an intellectual and a child, and it’s a comedy written by people who still assume that its audience is both literate and curious. As a critic once observed, “’The Simpsons’ is for people who read.”

Fox recently announced that Homer, Marge, Bart, Lisa and Maggie would return for a 29th and 30th season, making “The Simpsons” the longest-running sitcom and series in television history. A 30th season guarantees that “The Simpsons” will finally produce more episodes than “Gunsmoke,” the CBS Western that ran from 1955 to 1975.

It also means that “The Simpsons” will have endured at least five presidential administrations and span a television era from VHS tapes to online streaming.

The irreverent attitude, gags and references of “The Simpsons” have long been rooted in so-called “boomer” culture. By the time “The Simpsons” ends its 30th, and perhaps final, season, many of the oldest members of that generation will be well into their 70s.