<p>There are many different styles of variable names that I've come across over the years.</p>

<p>The current wikipedia entry on naming conventions is fairly light...  </p>

<p>I'd love to see a concise catalog of variable naming-conventions, identifying it by a name/description, and some examples.  </p>

<p>If a convention is particularly favored by a certain platform community, that would be worth noting, too.</p>

<p>I'm turning this into a community wiki, so please create an answer for each convention, and edit as needed.</p>

Sun published a list of variable name conventions for Java
here
.  The list includes conventions for naming packages, classes, interfaces, methods, variables, and constants.
The section on variables states
Except for variables, all instance, class, and class constants are in mixed case with a lowercase first letter. Internal words start with capital letters. Variable names should not start with underscore _ or dollar sign $ characters, even though both are allowed.
Variable names should be short yet meaningful. The choice of a variable name should be mnemonic- that is, designed to indicate to the casual observer the intent of its use. One-character variable names should be avoided except for temporary "throwaway" variables. Common names for temporary variables are i, j, k, m, and n for integers; c, d, and e for characters.
Some examples include
```
```
int             i;
char            c;
float           myWidth;
```
```