Open up marble/server/scripts/marble.cs. You should see something like this:
Code:datablock MarbleData(DefaultMarble)
{
shapeFile = ~/data/shapes/balls/ball-superball.dts;
emap = true;
renderFirstPerson = true;
// maxRollVelocity = 55;
// angularAcceleration = 120;
maxRollVelocity = 15;
angularAcceleration = 75;
brakingAcceleration = 30;
gravity = 20;
staticFriction = 1.1;
kineticFriction = 0.7;
bounceKineticFriction = 0.2;
maxDotSlide = 0.5;
bounceRestitution = 0.5;
jumpImpulse = 7.5;
maxForceRadius = 50;
...
The first part of this -- the MarbleData(DefaultMarble) part -- tells us what object this is. In MBP, this will say something slightly different. DefaultMarble is the marble's name. If you're not sure what the correct name is (e. g. in MBP, where there are a bunch of different marbles), just open the level editor, press Alt+C to switch to the camera, and look at the marble in the editor. It should say the name (plus a number) by a dot at the center of the marble.
Below the MarbleData line, you see a bunch of lines like this:
Code:(propertyname) = (value);
These are the properties of the marble. Modifying these in the script file will change the marble's default properties. Or you can open the console and type the following:
Code:(marblename).(propertyname) = (value);
Replace marblename, propertyname, and value with the marble's name (DefaultMarble in MBG), the name of the property you wish to change, and the value to change to, respectively.
Available properties:
-shapeFile: The file that the marble gets its shape from. This cannot be changed in the game, and I wouldn't advise messing with it.
-emap: Not sure; probably whether or not it uses environment mapping (if you've ever seen the marble reflect the sky, that's what it means).
-renderFirstPerson: Doesn't really seem to do anything AFAIK.
-maxRollVelocity: The maximum speed of the marble.
-angularAcceleration: How quickly the marble accelerates.
NOTE: The previous two appear twice in the file, the first time with // before them. These are commented out and have no effect. Change the non-// lines. (Interesting that the marble had those different properties at one point...)
-brakingAcceleration: How quickly the marble brakes.
-gravity: The gravity. You've probably heard of the famous defaultmarble.gravity = XX; before.
-staticFriction, kineticFriction, bounceKineticFriction, maxDotSlide: Just mess around with these to get a good idea of what they do.
-bounceRestitution: If the marble bounces, this is the factor by which each bounce decreases in height. A value of 1 means it will perpetually bounce; a value greater than 1 means it will bounce higher and higher; a value less than 1 means it will bounce lower and lower until it stops, like you would expect; a value of 0 means it acts like a Shock Absorber/Anti-Recoil; a negative value may crash the game!
-jumpImpulse: How high the marble jumps.
-maxForceRadius: Sounds like it affects how hazards work, I dunno . . .