I find that I sometimes need a Thank You card and never have any on hand. Today a couple one of which I will use now but the other I can save for later. Also Aud Sentiments and Natalie and Amy both have a Thank You Challenge. Wags and Whiskers and Crafting From the Heart both have an Anything Goes Challenge. CASology has a Clear Challenge. I'm not quite sure exactly what they are aiming for but the words thank you are clearly cut out of my card and left open to the inside so you have a clear view of the inside of the card. Artistic Inspirations has an Anything Goes/Thank you challenge as well.