What New Car is the Most Fun and Frugal Per Mile?

Today's Morning Shift 5th-gear and Volvosaurus-Rex prompted me to wonder....what is the most fun car with the lowest cost per mile ownership? I pointed out that Jalop green-car alternative the Jetta TDI Sportwagen is only a nickle more per mile that the soul-sucking Prius. Reader JonothanW8 chimed in that the BRZ and the Miata are only $0.56/mile. So, using Yahoo's Total Cost to Own Calculator (for consistencies sake and again to keep things the same factor 15k a year for 6 years) let's come up with a Best of Fun and Frugal Per Mile List.