If you check out any board game collection, you'll notice that one of the most interesting features is the suggest age range for each, from the preschool-aged range ones like Candy Land, to ones for somewhat older children (Hangman and Battleship is 8-Adult), and eventually grown-up ones for adults like Jeopardy! ("Teen to Adult" for the 1992 Tyco version) and Trivial Pursuit (Adult for the classic Genus edition).
But when it comes to watching the shows on TV themselves, a suggested age range may be a bit different compared to what the home version is, provided that there's even one affixed. Take Wheel of Fortune for example. Playing Hangman could easily be accomplished as early as kindergarten based on watching shows like Sesame Street, since there's lots of words that are learned prior to later 2nd/3rd grade. And quite honestly, I'd place Wheel of Fortune at "5 and up"; to me, the difference between "and up" and "to adult" implies a more serious, dedicated game that adults would enjoy watching like Jeopardy! (which I'd place at 8 to adult for the TV version).
Others IMO in terms of suggested age range (note: this implies material and not necessarily language/dialgoue that would make a show inappropriate for pre-teens):
Family Feud: 7 to adult (pre-Harvey), 10 to adult (Harvey)
The Price Is Right: 5 and up
The Chase: 10 to adult
Password (all versions): 8 to adult
Let's Make A Deal: 3 and up
Press Your Luck: 5 and up
Supermarket Sweep: 6 and up
To Tell The Truth: 10 to adult
Lingo: 7 to adult
Double Dare (Nickelodeon): 5 and up
Legends of the Hidden Temple: 7 and up
The Wall: 6 and up
Who Wants to be a Millionaire?: 8 to adult
Note: these ranges mostly differ from home versions of each game; at least as the viewer, you only see these as learning experiences since you're not actually competing. A first grader would enjoy the sets/numbers action in Jeopardy!, but would find most of material to complicated to really understand, similar to how I felt when I watched Jeopardy! as a young kid.