Most of the best SP episodes spoof some cultural or social fad or some weird news event...sexual harassment, global warming, UFOs, horror movies, icemen, the fetus lady (a real story from China), Wacko, religion, etc. I'm trying think of what's left to make fun of. Perhaps...
Forced Bussing. The boys are bussed into downtown Denver and become home boyz, people die.
Psychic Hotline. The boys get into horoscopes and stuff, people die
Martial Arts. Spoof a Honk Kong movie, people die.
Viagra. Use you imagination, people die.
Gill Bates. The tycoon who takes over everything, people die.
Title 9. The boys lose their football team, switch to synchronized swimming, people die.
The Music Man. A traveling musical instrument salesman comes to town, people die.
The Phantom. Cartman becomes deformed, lives underground, people die.
C-SPAN. The c-span bus comes to town, people die.
The Plague. Yes, the plague is back, bigger than ever, everyone dies but Kenny.
God vs Allah. Comedy Central is car bombed, Matt and Trey die.
rAD
BTW, very few shows remain any good after three years. Star Trek got cancelled before it had time to get really crappy. Dick Van Dyke quit after 3 yrs (I think). That's why all those shows were good. But maybe if our culture can continue to manufacture new stupidities, SP can go on indefinitely!