Preprocessor Commands and AVR commands

Hello! I am interested in learning some AVR commands and preprocessor commands. I already know some, such as #define, #include, and using the sleep library. Does anyone have a link, etc. to a place that talks about these codes? I want to know if there are some cool tricks, etc. that you can do with Arduino using these commands. Oops! I just realized that I put this topic in Project Guidance instead of Programming Questions! I thought I did. Maybe someone will move my topic. Thanks

define and #include are part of the C-language.

What kind of tricks are you trying to accomplish? With all of the libraries and C-code available, why bother playing around with the pre-processor?

By "tricks", I mean manipulating the Arduino in ways that could not be accomplished using the Arduino library alone, such as sleep, or manipulating constants in AVR libraries, etc.

dkl65: Maybe someone will move my topic.

Next time, ask. I suspect a moderator will take care of it without complaining (too much). ;)

manipulating the Arduino in ways that could not be accomplished using the Arduino library alone

http://arduino.cc/forum/index.php/topic,104712.msg785298.html#msg785298

...and, of course, the datasheet for your processor is required reading... http://www.atmel.com/devices/atmega328.aspx?tab=documents

http://arduino.cc/forum/index.php/topic,104712.msg785298.html#msg785298

That is a link to a similar post I made, asking for a link to "Advanced Arduino Language" (C/C++).