Driving home from school today, I was slowing as I approached a stop light (randolph rd. and new hampshire ave. for all Marylanders reading this) .... when the oil light came on, engine became barely responsive, and steering wheel had to be wrestled violently to get the car to coast into a small strip mall.
I popped the hood...and crawled under the car... and there was a fresh black oily sludge coating the underside of the engine (oil pan), rear of engine (all over transmission housing and rear block) and even up onto the valve cover.
Checked the oil - was low, but nothing serious. Added a quart, didn't notice any oil dripping onto the ground or anything afterward - in fact, the pavement was completely dry where the car was parked.
Meanwhile, car refused to start. Turned over endlessly, but no start. With the hood popped, I could see the engine rock back and forth, but it just wouldn't go.

Anyone had a similar experience, or have any advice?

I plan on fixing this car myself... it just turned over 201200 miles, I've nursed it since 165 or so... other symptoms prior to it's demise today were: ocasional heavy clunking noise when accelerating after switching gears (it's a M46)... I think the radiator is leaking because I lose coolant very slowly over time... yet there is absolutely no trace of coolant on the block - at least, none that I can see... high idle, which can be brought down by giving it a little gas. When it does "come down" it will idle poorly in a cyclical pattern where a second or two of normal running will be followed by a drop in RPM and a simultaneous dimming of the lights. Occasionally things will even out and it will idle ok.

Car is now sitting peacefully in my driveway. Help, please!

Evan