Some applications need fancy things like rounded (or other exotic format) buttons, leds that glows, and other full graphical widgets, difficult to emulate with the regular tk widgets. Think on Winamp(TM) or other mpeg3 sound players.
Here is my try on that. A customizable set of widgets drawn on a canvas. Its behaviour is very primitive yet, but enough for my needs. I used it inside my VebKlaso Player, http://vebklaso.com , a online synchronized audio presentation system. There is a pdf User's Manual at the site. Here are a couple screenshots of the player with custom interface:
http://pragana.net/images/vkplayer1-small.jpg
http://pragana.net/images/vkplayer2-small.jpg