Minecart Tracks [b]
Minecart tracks are exactly what they sound like. You lay them down, and you
place upon them any of the minecarts mentioned above. They can go up or down
the sides of blocks in ramps in slopes ranging from very gradual to almost
vertical, breakneck, suicide slope steepness. They are placed by
right-clicking on the ground where you want to place them. They will
automatically make corners when a piece is laid between two other pieces that
are at a 90 degree angle.
Note that minecarts collide on tracks, but you likely knew that already, or
you could've figured it out for yourself.
There also used to be a minecart glitch, and I'm not sure if Notch fixed it in
an update. It used to involve making a square of track around one block, and
placing minecarts on it until they perpetually hit each other and went around
the track really fast without slowing down. You'd then put a track next to one
edge, and a minecart placed on this track got hit by the others and was
launched along it's own track really fast, and didn't slow much on even the
steepest hills.