Thanks to Harriet Kim for posting how "How to create a Calendar that runs on the 1st Saturday of every month". It helped me with this rolling calendar keyword that falls on the 2nd Thursday of every month.
Create a Calendar object
2. Create a Weekly keyword, THURSDAYS (under Keywords, right-click > New keyword > Weekly)
3. Create a Monthly keyword, LAST_DAY_OF_MONTH (under Keywords, right-click > New keyword > Monthly)
note: I selected "end" in the drop down because the "beginning" of the month would cause the rolling keyword to skip counting the first Thursday of the month when the 1st landed on Thursday.
4. Create a Roll keyword, 2ND_THURSDAY_ROLL that falls on the LAST_DAY_OF_MONTH and rolls to the THURSDAYS keyword.