I've read a few Instructables about playing with school computers in which people complain about how difficult it is to open Command Prompt. Yes, you can usually find a way past the school restrictions, or you can download Command Prompt Portable from portableapps.com, but I have a batch file that will do the exact same thing.
Step 1: The Script
title @ %CD%
set/p "command= +++> "
Save as a batch file (CMD Commander.bat, All Program Files), and run it. You now have a portable Command Prompt that is only a few bites in size (miniscule)!