I lost two quarts in 5 minutes last night... now not losing any?

[Crunkrich]

Last night after a little spirited driving, a friend and I went to a skatepark for a few hours. When we left I heard a ticking then a knocking sound from the engine, and if I didnt stay on the gas it would have died. At a stop sign it did die, and couldnt start it until I got a jump. Drove to a BP 1/2 mile away and went to get oil to because I suspected it to be low.

After I poured in about 1/2 a bottle, my friend saw a big puddle of oil under the car that had just leaked out, like in 30 seconds it leaked out. And the car would start and run, but I didnt want to drive it so it was towed home.

Ok, background story done, now the problem and what I've got so far...

The car started back up again today in my driveway, and it was still knocking if I revved the engine (couldnt hear it under idle). We pulled the spark plugs to figure which cylinder it was, and when we pulled #1 the knocking stopped.

The part I dont understand at at: I put more oil in like we did last night, but it didnt leak out like the gusher the night before. Just a small trickle, leaking down off the top front of the oil pan.

So it leaked like crazy last night after ?whatever happened? and it started knocking. #1 cylinder. Leaks off the top of front of oil pan, but we couldnt see where it was leaking from exactly.

Any ideas? If it cracked the lower part of the block could the crack have been bigger when it was hot, and the next morning it had cooled and 'closed' a bit, not letting the oil leak so fast? Its only a drip now.

I'm kinda stumped... any help would be great