Put On Layer
Allows you to easily move entities and their nested elements (ie groups within components within groups) to any layer. You just right click on an entity you want to move. You'll see a "Put on Layer: " submenu. The first entry is "Current" then all other layers in the file are listed underneath for quickly moving entities / groups / components to different layers.
Original version was "PutOnCurrentLayer.rb" which always put the selection on the currently active layer. Thanks to Jim H (jimij5) from the SketchUp Ruby forum for the idea to add the ability to put entities on any layer without having to actually change the active layer.
Originally based on "layer.rb" - "change to current layer" by zdarc. However, other than the include statement this script is entirely custom. Without layer.rb as a starting place though, I may have never even bothered implementing this... Thanks wehby for the prompting to checkout Windowizer.rb which uses a dynamic right click menu. That helped me get my head around what I needed to do for this.