One of my favorite video games of all time simply has to be Mario Kart: Double Dash on the Nintendo Gamecube.
It is devious in its cartoon mayhem, like you're in one of the old Tom and Jerry cartoons. It's one of those games that is replayable. As you proceed to get better and win, there are prizes. One of the prizes, on what is really quite a difficult level of 150cc (there are probably Nintendo gamers out there that would scoff at this still being difficult but I've never completed it perfectly so it is apparently at just the right skill level for me to be a challenge yet still winnable--off topic, I once had this generic basketball game on the regular old Nintendo and I got so good at it, that I would have to beat the computer team by 100 points for it to be a challenge, so what fun is that? But I digress...), the prize is a "mirror" world where the courses are the mirror image of what you memorized already. So the game really does become "new" again without anything really new.
Plus, as Morgan has grown up, she now gives me a run for my money. Hence, that is a new challenge. It will be new again when Madison gets older, as she can barely keep the A button down right now.
The cartoon madness makes it a lot more fun than a regular racing game to me. Every course is different by definition because new obstacles and turtle shells are thrown at you all the time.
It's different. It's just plain fun. That is the sign of a really good video game to me in this day and age, just being plain fun.