The TweenService has finally been enabled! Tweening with the TweenService is similar to Tweening with GUIs, except the service allows you to tween other properties of other objects, such as the Position of a Part or the Color of a Decal. Here's how to use it:

1. Create a TweenInfo object using TweenInfo.new(). Here is the syntax:

TweenInfo.new(float time, EasingStyle easingStyle, EasingDirection easingDirection, int repeatCount, bool reverses, float delayTime)
All of these parameters have defaults.

2. Create a dictionary in which the keys are the names of the properties you want tween and the values are the target values for the properties. Not sure what the property limit is. Example:

local tweenTo = {
  CFrame = CFrame.new(), Transparency = 1, Color = Color3.Random()
}
3. Invoke the Create method of the TweenService, passing the Instance, the TweenInfo, and the property dictionary as the parameters. It returns a Tween Object.

4. Use the Play(), Pause(), and Cancel() methods of the Tween to tween the properties.

For more information, go here:

wiki.roblox.com/index.php?title=API:Class/TweenService

wiki.roblox.com/index.php?title=API:Class/Tween

The Trail just appeared on the wiki today. Unfortunately, it is currently disabled. It's used to create that kind of effect where you wave a glow stick around in a dark room. It's gonna be pretty sick.

For more info:

wiki.roblox.com/index.php?title=API:Class/Trail