Our 43rd president (or a reasonable facsimile thereof, courtesy of Will Ferrell) invites viewers to “remember, celebrate, and cherish his eight years of service,” in this HBO special shown live from the stage of Broadway’s Cort Theatre. Ferrell’s impersonation, first created during his years on Saturday Night Live, has earned largely positive reviews during its eight-week run; the political satire is not particularly pointed, but no one captures Bush’s cowboy cadences and Peter Pan jocosity better. And the improvisatory portion of the show, in which Ferrell assigns Bush-style nicknames to audience members based on their occupations, promises to be a highlight. Saturday, March 14, at 9 p.m., HBO