Former Palm chief Jon Rubinstein has left Hewlett-Packard, having completed the 24-month commitment period he agreed to when HP acquired Palm. An HP spokesperson has confirmed the story, first reported by AllThingsD, in a brief statement: "Jon has fulfilled his commitment and we wish him well."

Rubinstein rose to fame as a hardware guru at NeXT, ultimately joining Apple after the company acquired NeXT in 1996. He was instrumental in developing the iMac and PowerMac desktops before spearheading the iPod project that would herald the company's business dominance. After retiring in 2006, he joined Palm to revitalize the flagging device maker's fortunes, developing the Palm Pre and WebOS software before being crowned as its CEO in 2009. A year later, Hewlett-Packard purchased the company for $1.2 billion: but just a year later, pulled the shutters down as Rubinstein was shifted (or "dumped") to a "product innovation role" within HP, where he saw out the last of his retention period before departing. In a terse comment to The Verge, the man himself has said that he's "going to take some well deserved time off," and after the last twelve months, we wouldn't blame him.

What do you do with that once state of the art Power Mac? Well, you could always empty the case and add a "cheap clock mechanism," in the words of our friend Justin -- who emailed us some pictures of his latest creation this morning. But don't forget the Mighty Mouse pendulum: that's what really won us over. Hit the source link for more glamor shots.

Update: We just received an email from Justin, who inexplicably left out one crucial detail: this thing plays the Mac startup tone on the hour. Super geeky, or super annoying? We'll let you decide for yourself (although we suspect it's a combination of the two).