Facebook employees who don’t want to wait for an IPO (and it doesn’t look like one is coming soon) now have another way to cash out their shares. Russian investor Digital Sky Technologies, which in late June bought a 1.96 percent stake in the company for $200 million, is offering also to buy up to $100 million worth of common stock owned by existing shareholders at a $6.5 billion valuation. Digital Sky had already indicated at the time of the initial deal that it would make an offer to buy “at least” $100 million of stock held by Facebook employees. The $6.5 billion valuation is far below the $10 billion valuation Digital Sky put on the company when it purchased its 1.96 percent stake, although that deal was for preferred stock, not common stock.