Well, let's answer this one at at time.
"fun-to-drive". Any car can be fun to drive. I've driven a armored personnel carrier that was fun to drive. So that doesn't narrow it down at all.
"fast" - Compared to what? Highway speed fast? Faster than a shopping car? Faster than 200 mph? Any car you get, will be able to go highway speed, and that's as fast as you can go, legally. So, again, that doesn't narrow it down.
"sporty" - Define that. Actual sports car like the NSX, or sporty like the newer Civics that have nothing "sport" about them?
Why below 70k miles? A car can have 20,000 miles, and be a piece of junk. Miles don't tell you anything, except how far it was driven. Doesn't tell you how hard it was driven. How it was maintained. Whether it was raced, or really any useful info at all.
So, based on the sheer vagueness of this question...there's no way to give you an actual answer.