And another idea for a control:
Imagine you've a control which blends down the whole form and makes a spot anywhere. I think you could place a picture for this over the whole form which has an opacity of about 30 percent and a transparent color specified. You place then a filled circle in this transparent color on this picture and voila - you've your spot.
for example for making tutorials for using complicated programs: You can "dim" the whole form and show a "spot" on a special button while you explain some features of this button in an extra textbox.
or for example for cool splash screens where event two or three spots drive around on your Logo
Ok, I think you know what I meant ;-)