fun

I'd look first to the Mazda 3. It's a 2 liter with 155 hp in a 2900 lb car, and still gets good milage There's also the 2.5l engine option for more power. Then maybe a Honda Fit; a little less power; a little lighter; a little bit better interior reconfigurability. Both handle fairly well for what they are and handling can be improved with swaybars and the like if you're so inclined. There are cars that get better performance (GTI, Ford Focus and Fiesta hot hatches, Nissan Juke etc.) but they're going to cost you more upfront, in maintenance and in gas.

I'm guessing the '85 Suburban kept you un-bored because you had to constantly work to make money to keep gas in it? Maybe a $12k mid 00's Escalade would keep you in a similar state of un-boredom?

mwcten nailed my two top picks. But if you want a new car for $12,000 (is this what you meant to specify?), that's going to be tough. The only new cars you'll find at that price aren't especially good ones.

The closest I've seen, and I don't know if such deals are still available, are leftover decently equipped Ford Focus hatchbacks that went for about $14k a few months ago. The Focus isn't as reliable as the other two, but with a manual transmission (if this is something you prefer or are open to) it's not too far off.

Up around the $15,000 MSRP range (add $1,000 for an automatic) you'll find the Hyundai Accent, Kia Rio, Nissan Versa Note, and Toyota Yaris. None of these is as practical as the Honda Fit, but you can probably get them for less. The Hyundai and Toyota are most fun in their sport trims, but then are priced well above your limit.