Originally released  as a part of the Windows Media Bonus Pack for Windows XP, in 2001, Yule Log visualization hadn’t been updated in years and didn’t work with newer Media Player versions. Now, Sean Alexander posted an updated Yule Log Visualization for Windows Media Player 11/Vista/XP.

After installing, just go to Now Playing>Visualizations>Yule Log and fire up your music (sorry I couldn't resist).  If you want to tweak the effect, choose "Options", then select the Yule Log Visualization and click the Properties button.  You'll find a slider for sensitivity.

Source:→ Ed Bott