It's hard to imagine too many people that would qualify for this. If someone already dislikes a series, it's hard to imagine them liking a spinofff, because the traits they disliked will probably be in that spin-off. Maybe widen the parameters to 'series you didn't care about' or something broader.
To give an example, people who don't care for shooters wouldn't play Gears of War, but may like Gears Tactics because it's a tactics game instead. If people dislike Gears of War, it's probably because they don't like the overly masculine designs and gratuitous violence. In which case they still won't like Gears Tactics or any spinoff regardless.
So personally, I'd say Crash Nitro Kart for the original Xbox. I never owned Crash Bandicoot games growing up, but Crash Nitro Kart was perfect for Xbox which came with 4 controller slots (opposed to PS2 which required buying a multi-tap, and then buying another when you realised PS2 slim uses a different version), and so I played that a lot with family.
I'll aslo throw in World of Warcraft, since I never played the Warcraft games.
