This site provides resources for two GIS courses: FRST 182 and GEOG 328. 

How to register the Spatial Analyst extension for home/laptop use:

Click Start > Programs > ArcGIS > Desktop Administrator

Click folder Single Use and Extensions

Click Register Now button ... the following screen should appear ...

Click Next ... be sure you are connected to the Internet ...

Click Next (3 more times I believe)

     ... a screen will have your Registration number **no need to alter it **

Click Next

"tic" the Spatial Analyst extension

click Next ... and follow the rest of the remaining prompts.