Top 10, plus why they made my list:
10) Hollywood Squares
Who doesn't like seeing stars cracking wise? Easy, but with just enough strategy involved to get you thinking. Probably an unpopular opinion, but I prefer the Bergeron run even over the Marshall run. Easily one of the best modern(ish) revivals. You can tell everybody involved is having a blast.
9) Concentration
One of the best shows to play along with. It's a smart show that anyone can play, although it requires, well, concentration. Those excruciating rebuses was often much harder than they needed to be, but very satisfying to crack. The creative prizes (everything from "banana peel" to "swimming pool") were fun too--you never knew what they'd turn over next.
8 ) The Mole
Some would exclude this and call it "reality", but think of it as a a studioless long-form game show. It's still contestants competing against each other in a game of skill for a cash prize. And with The Mole, there's never a moment where you can say "THIS part is game, but THIS part is reality kerfuffle." Truth is, even those "reality" elements all part of the metagame. Your task as a viewer is to figure out when you're being misled.
Awesome music, awesome production values, and an awesome concept. It sucks you in and demands that viewers bounce a few conspiracy theories around to make sense of it all. I have to give a show like this high marks.
7) Press Your Luck
Light on "game", but among the very best when it comes to "show". I'd love to take a spin that giant, colorful board. The Whammies were iconic, Tomarken could whip the contestants into a frenzy, and it always felt like ANYTHING could happen.
6) Password
It hasn't aged as well as some other games on the list, but it's simple and brilliant. Communication is universal. It demands you play along and inwardly compare your words to the contestant. Watching TV shouldn't make you think this much, but Password pulled it off.
5) Who Wants to Be A Millionaire?
Surprised only one other person has named this. It's influenced nearly every show that's come out since 1999, yet it still holds up as one of the best shows from that era. The questions were great, Regis was an incredible host, and it produced more unforgettable, tense moments in its first two seasons than many shows produce in their entire runs. It's experimented with different hosts and formats over the years, but at its core it's always just been a great Q&A game.
4) Family Feud
I'm convinced that Family Feud is a perfect format. Of all the shows on this list, it's the hardest to screw up. The show's endured Richard Karn, "celebrity firefighter ex-wives" specials, "dick joke of the day" questions-- but even on a bad day, Family Feud's survey format is brilliant and can get people yelling answers at their TV.
3) Pyramid
Most of what I love about Password can be repeated here, but I find Pyramid is just a smidge more fun to watch. Winners' Circle was, and is, amazing television. It rewards creativity and out-of-the-box thinking. And it lets you see what celebrities are really like when they're forced in a quick-thinking, high-pressure environment.
2) Sale of the Century
A few days ago someone compared Sale to a serial that built on itself day by day, and I agree. I love everything about it--the format, the prizes, the crazy sketches--it's a brilliant concept executed perfectly.
Sale is ALWAYS building drama towards something or another, whether it's the end of a question, the end of a speed round, or the massive jackpot. Jim Perry was a pro who could make any contestant likable, and go from question master to manic salesman and back in a heartbeat. The show's format often kept games close and exciting, and the insane prizes up for grabs made the show really stand out. Love everything about it and it's the show I'd most love to see rebooted properly.
1) Jeopardy!
Pure Q&A. No show has better writing than Jeopardy. It knows exactly what it wants to be, and it hones in on it in its simplest form, with just enough trappings to keep it varied.
A lot of other shows put emphasis on the prizes or the contestants, but Jeopardy is first and foremost a showcase for the material. On Jeopardy, the questions (er, answers) are the star. It does the best job of making the viewer feel like you're THERE, answering questions about literature and capitals and word puzzles along with the contestants. It's immersive, satisfying, and the absolute best at what it does, so it gets the top spot.