Can you figure this out?

[Neablas]

OK, I've been hearing this knocking noise coming from my engine, but it'll only happen when I start up my car, after it's put in gear and driven for a minute the noise will go away. And if i were to turn off the car and wait about five minutes and restart it, it would happen all over again. I've heard this for the past little while and only recently (tonight) I'm seeing oil what appears to be coming from the bolt (and creating a small puddle) on the lower intake manifold. Any ideas? I personally am thinking busted gasket seeings how it's an orginal gasket (180,000 Miles +), but how would the explain the knocking? BTW. the engine is in great shape and runs strong. ... incase you were wondering.

thanks a million in advance for any help.