Titan tickets, but be creative and mail them to her. It's weird because the sister-in-law you speak of just moved.. I'll message you her new address.
I kinda like mine, she's nice. I wasn't gonna buy her anything but then she asked me what I wanted from her, so now I'm on the hook. I have no idea what to get her. She likes Big bang Theory and chocolate LOL, thats all I have to go off of.
Get a gift card and note the ID#. If you get it back for your birthday you know she's a ***** (and will have done what mine does)
Unless you enjoy buying a gift for her, I'd make the wife do it. If the wife isn't willing to do it, then there is the gift card route. Not personal but safe. Then there's http://www.buycoolshirts.com/bigbathamsit17.html?gclid=CPKTt9bD7bMCFQ45nAodqBgAmw