Soldering every circuit you build probably isn’t practical.  At some point you are probably going to want to use some type of temporary method to connect different components together.  One of the popular methods is using a breadboard.  This simple (and cool) looking device only needs a few instructions before you can begin

A popular LED project is the “Larson Scanner.”  This scanner emulates the effect seen on KIT from Knight Rider and the Cylons in Battlestar Galactica.  The code is usually written using “delay()” which means you can’t combine it with anything else.  The following code could be put into a function, called periodically and allow your code to scan while doing other things.