Option bulls have converged on Sirius XM Radio Inc (NASDAQ:SIRI - 2.80) today and are targeting short-term upside in the shares. Overall, call activity is running at more than six times standard intraday volume, and is trumping put volume by a factor of 12.

The most active strike -- by a generous margin -- is the December 3 call, where nearly 38,000 contracts have traded. Today's volume has included three large blocks (of 10,000, 5,000, and 2,000 contracts), all of which crossed the tape at the ask price of $0.02 per contract. With implied volatility on the rise at this strike, it's reasonable to assume some buy-to-open activity.

The puny price tag is due to the likelihood of these short-term calls actually expiring in the money. In order to be profitable by next Friday's close, SIRI shares need to rally above $3.02, which is 7.5% from the stock's current perch (and north of SIRI's annual high of $2.97). The stock goes ex-dividend tomorrow, which makes this an even more challenging trade, as the share price will be adjusted to account for the five-cent distribution. The call's delta is a measly 14%, meaning the stock has just a 14% chance of conquering the 3 strike by the time the options expire.

As is frequently the case with low-priced stocks, calls are the more common destination among options players. The 50-day call/put volume ratio measuring buy-to-open activity at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) stands at 9.00, meaning nine calls have been purchased for every one put during the last 10 weeks.

Despite being priced for two pennies each, however, today's calls were no bargain. Implied volatility for these bullish bets stands at 43%, well above SIRI's one-month historical volatility of 24.6%. Schaeffer's Volatility Index (SVI) for SIRI, additionally, has recently dropped from near a six-month high of 55% to 47%.

The stock itself, meanwhile, has been hesitant to pick a direction in recent months, instead shuffling sideways within a range between $2.70 and $2.90. This consolidation has driven the shares into their 20-week moving average, so the stock could be at a breaking point. Today's aggressive call buyers are hoping to see a shift higher in the near term, but a breach of this trendline could prompt an acceleration in selling activity.