What is the most FUN pair of speakers you've ever had and why?

Not the most expensive, not the best reviewed, not the biggest, but the most FUN.  You know, that ONE that just makes you throw on some more music and keep listening, the one that makes your toes tap, your head bob, your ass move the most.  The one that makes you think to yourself "damn, why doesn't everyone have a pair of these?" Let 'er rip. 
Great thread. I second the Klipsch Forte III. Really had the boogie factor. I will also say my Klipsch Heresy III were fun as well. Alas, life throws us curve balls and things change. I'd take the Forte III's back in a heartbeat..
Sound Lab Quantum
Excellent electrostatic hybrid
great integration with otl amps
Legacy Whisper. I had more lengthy listening sessions with them than anything I have owned.