Snow'ed is an easy-to-use desktop application that puts a window on your desktop.
From the menu bar you can choose options like different color window frames and how much snow to fall.
Please read the documentation for more detailed information.
Open the application. After 5-10 seconds the animation should smooth out. The delay is a result of the loading of resources and allowing the system to continue to do work at the same time. However, If the animation remains jerky, make sure Control Strip is hidden if it is visible, and quit any other applications that are running. Requirements: PPC Mac; a color-capable Mac/monitor; thousands of colors minimum; 24-bit (millions) recommended for best looks.