RPN FTW! I was never able to lend my calculator out because it took too long to explain how it works. I got (and still have) a copy of the Advanced Programmer

RPN FTW! I was never able to lend my calculator out because it took too long to explain how it works. I got (and still have) a copy of the Advanced Programmer's Manual for the HP 48G. Great environment for someone to learn programming while you're bored at school.