This week brings two major competition shows, a genre that has produced past staples like "Survivor" and "American Idol." They land at a time when network ratings have been drifting downward, while some of the unscripted franchises that once buoyed viewership have begun exhibiting the attrition that comes with age."Titan Games," produced by and featuring Dwayne "The Rock" Johnson, is basically a mix of massive obstacle-course-like challenges — using a kitsch-y Mount Olympus mythological theme — bearing a resemblance to the one-time syndicated hit "American Gladiators."Fox, meanwhile, tries to fill the void that "Idol" left in its lineup with "The Masked Singer," a bizarre musical showcase, where celebrities (or those billed as such, since the identities haven't been revealed) in ornate costumes sing in front of a panel and audience, which must then try to identify them based on the performance and cryptic clues.If the concepts sound gimmicky, they are, while hewing closely enough to established franchises to provide hope that they might be able to break through, in the same way that, say, "The Voice" did. But that was back in 2011, and while there have been other unscripted successes — like NBC's kids talent show "Little Big Shots" — there arguably hasn't been another reality-competition smash since then.Inevitably, the hunt for hits also includes reaching back to the future. USA network, for example, is reviving "Temptation Island" — an early dating program that triggered controversy when it premiered on Fox in 2001 — in mid-January.Johnson certainly brings star power to "Titan Games," while setting a near-record for sports clichés in just the portion of the premiere that was available for preview."I wanted to redefine what an athletic competition can be," he says, noting that the over-the-top challenges — with names like Herculean Pull — are "inspired by the workouts that have fueled me."Based on a South Korean format, "Masked Singer" is hosted by Nick Cannon, with Ken Jeong, Jenny McCarthy, Nicole Scherzinger and Robin Thicke serving as judges and providing lots of wide-eyed reaction shots at the celebrity participants — who are gradually exposed, one per episode, after several elimination rounds.Based on a sampling of the two shows, both possess a fairly high degree of energy, if not much in the way of ingenuity. What "The Masked Singer" has going for it is an unabashed goofiness — some of the costumes look like monsters from "Mighty Morphin Power Rangers" — which, if history is any guide, might not wear especially well once the novelty wears off."This comes down to who wants it more," Johnson says dramatically, sounding like a football analyst during one "Titan Games" event.The networks clearly want another reality hit badly, but based on recent history, establishing a new one represents a different sort of Herculean feat. And if these shows don't work, the masked singers might not be the only ones who will be inclined to hide their faces."The Masked Singer" premieres Jan. 2 at 9 p.m. on Fox. "The Titan Games" premieres Jan. 3 at 8 p.m. on NBC.