On the call side, Motorola Mobility (NYSE:MMI) calls are trading at 10 times their average volume after several investors bet bullishly on the company. Gold Fields (NYSE:GFI) calls are trading at just under 10 times their average volume on news that the company is purchasing an interest in several mines from IAMGOLD (NYSE:IAG). Human Genome Sciences (NASDAQ:HGSI) calls are not far behind, trading at just over 9.5 times their normal volume. USEC (NYSE:USU) calls are trading at 9.4 times their average amount on news that China could release a Nuclear safety report soon, which could have a positive impact on Uranium manufacturers. Finally, Expedia (NASDAQ:EXPE) calls close out the list at 7 times their normal volume after the company received an analyst upgrade.Taking a look at the put side of the ledger, EXCO Resources (NYSE:XCO) puts are currently trading at over 9 times their average volume on news that the company is looking to go private. Eldorado Gold (NYSE:EGO) puts are trading at close to 8 times their average volume after several investors bet bearishly on the company. Tesla Motors (NASDAQ:TSLA) puts are also very active today, trading at 7.3 times their average volume after company announced that they will be discontinuing their Roadster model. STEC (NASDAQ:STEC) puts are trading at just under 6 times their average amount after the company received a neutral rating by analysts. Finally, Bank of New York Mellon (NYSE:BK) puts close out the list at just under 6 times their average amount.