The deal is good at participating Starbucks stores in the U.S. and Canada as well as at Teavana Fine Tea + Tea Bars (which currently only has locations in New York, Seattle, and Chicago), while supplies last.
While you don't actually have to bring your mom or even give either of the drinks to her, it'd probably be nice to do so.
The Oprah Chai Latte was developed in partnership between Starbucks' Teavana brand and Oprah Winfrey. It features a blend of cinnamon, ginger, cardamom, and cloves along with loose-leaf black tea and rooibos.