Here are some really basic (but useful) functions that returns random stuff…

The really basic one, is built in the Flash api and it returns a Number between 0 and 1:

var n:Number = Math.random();

A number in  a range

Sometime is more useful to have a random number in a different range, let’s say between 15 and 45, instead of 0 and 1.

public static function randNumber(max:Number = 1, min:Number = 0):Number {
    return Math.random() * (max - min) + min;
}

Random int

and what if we don’t need decimals? Round’em!

public static function randInt(max:Number = 1, min:Number = 0):int {
    return Math.round(Math.random() * (max - min) + min);
}

Random boolean

True or false? Flip a coin.

public static function bool():Boolean {
    return (Math.round(Math.random()) == 0);
}

Random sign

-1 or 1; Useful when you have to random select random rotation verse, for example, -1*45 or 1*45, rotates counterclockwise or clockwise.

public static function sign():Number {
    return (Math.round(Math.random()) == 0):-1:1;
}

Random color

Really useful when drawing debug shapes on screen..

public static function color():uint {
    return Math.random() * 0xFFFFFF;
}

Random point

Inside an area. I like to use the flash.geom.Rectangle struct to describe an area, more than using 4 parameters (Flash api are quite inconsistent about this choice)

public static function point(area:Rectangle):Point {
    return new Point(randInt(area.x, area.x + area.width), randInt(area.y, area.y + area.height));
}