Anyone knows a source, website where I can get some good implementations of 3D intersection algorithms, like
http://www.realtimerendering.com/intersections.html.
It's a huge matrix of algorithms that calculate intersections between various types of objects. Excellent resource.
Graphics Gems is a good place to look for this type of thing.
You might want to put Eberly's Game Engine Design on your bookshelf. It has detailed algorithms and discussion for each of the intersections you've listed.
If you're doing raytracing, then asking at ompf.org and looking through the RTNews archives might help. In any case, it depends on what you're going to use these for.
Not really a website, but this book Real-Time Collision Detection is well worth it for what you are looking for.
The source code for the POVRay ray tracer has some implementations that may be of use.