1) “American Ninja Warrior,” 8-10 p.m., NBC. The summertime reality shows are starting to wrap up now. For “Ninja” (shown here in a previous episode) this is the last of three semi-final rounds, with side-by-side races; next week, the survivors go for $250,000.
2) “Dancing With the Stars: The Next Pro,” 8-9 p.m., ABC. And here’s another show that’s a step away from a winner: The final four dance with pros from “Stars”; then one is eliminated. Next week, Derek Hough and Witney Carson return and one of the final three will be the next “Stars” pro.
3) “It’s Always Sunny in Philadelphia,” 9-9:34 p.m., FX and FXX. These folks are well-suited for the bar they run, not so well set for college. Now, alas, all of them are on campus; Frank even imagines matching Rodney Dangerfield’s life in the movie “Back to School.” The result here is chaotic and generally quite funny.
4) “POV: How to Build a Library,” 10 p.m., PBS. Nairobi’s oldest library opened in 1931. A neo-classical beauty (built mainly with Carnegie money), it was for whites only until 1958, when Kenya’s independence neared. Now two women lead a crusade to rebuild and restock it. This documentary is slow at times, but shimmers with idealism.
5) “The Chelsea Detective” season-finale, www.acorn.tv. A rich man plummets from the balcony of his own hotel; now suspects abound. It’s a smart case, probed by likable people. This wraps up a season of four movie-length tales; with the exception of the second one, all are excellent.
— Mike Hughes, TV America