DropBar by Cool Focus
DropBar is a 2-level fading and sliding horizontal menu which initially looks like a simple button bar (and can be used that way). Hovering over a first-level button can reveal a second level of buttons below. Items can use gradient fills. The second-level strip expands into and out of view vertically, and buttons fade between colors. DropBar supports sound effects, and full customization of colors, fonts and behavior.