Peggle is a simple puzzle game from PopCap that seems to possess some sort of mystic time-sucking power, where once you start playing, the next glance at the clock will have you shocked at the length of time you’ve been entranced. Check it out, unless you don’t want your day to be wasted 
Loved that game. A ‘half-life’-ified version came with my Orange Box.
ups, i thought it is a flash game you played on the browser, but then saw the download link /: