There are plenty of stocks each month with extremely high IVs. Some of these are biotech stocks or or stocks waiting on important news. Price is guaranteed to move dramatically, and IV is nearly guaranteed to collapse when the news is released. Since a straddle is often too expensive, why not do an IV play? Okay, so we can try to do a calendar? How would one set it up so that only IV would affect the spread, and not movement of the underlying asset?