She is driving 5-hrs from KS to come stay with my boys for 2 days while DH & I getaway for the weekend to celebrate our 10th wedding anniversary! I have 2 sisters who live within 30mins of my mom and she does on-the-spot babysitting for them all of the time and this is the first time she's ever done anything like this for us. We are a military family and lived in AR before moving to TX. I don't want to offend my mom and do nothing but don't think I should do something over the top either as theses are her grandchildren after all. So what do I do? Is a thank you card enough?