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

My first really fun set of speakers were a pair of Henry Kloss’s large Advents. They were clean, clear, great bass, terrific for everything from rock to classical. They demonstrated the value of acoustic suspension designs and were absurdly inexpensive. 

My parents still have a pair of the advents . Lot of good times had with those. 

The Advent was my entry into the hifi world as well, although I cannot recall what they sounded like other than that they were good.

It was the fall of 1971 I was a junior in HS and I used every dollar I made bussing tables at a restaurant down the shore over the summer to buy a system package from a chain outfit called Tech Hifi in Bryn Mawr Pa.  The package consisted of a Dual 1219 turntable, a Harman Kardon 610 receiver and a pair of Large Advents.  The whole thing retailed for around $600.  I hooked it up in my bedroom and listened to Tumbleweed Connection.   Pure bliss.   It was the moment that I became an audiophile.  I never looked back.  While my current rig blows that little system away I still have a great deal of fondness for it.  I attribute that to the Advents.

B&W DM 602s

Driven by an Acurus A80, B&K Pro 5, and Cambridge Audio CD6. Interconnects were Nordost Black Knight, SC was Kimber. 

Right out of college, this system was dynamic, authoritative, and played at extremely loud volume with clarity and great fun.

Terrific speakers for a party.