I had a Tervis Tumbler up until this past week when I found out that they don't survive a "tumble" off the counter.I loved it, though, for hot and cold drinks. It didn't really hold in the heat, but I liked the size I had. They would make great gifts.
If you still have it, send it in and they'll replace it! They have a lifetime guarantee. I looked at the form and it doesn't appear that they require proof of purchase, or original receipt, which is great! I hadn't had a reason to actually look into the guarantee until now.
http://www.tervis.com/info/lifetime-guarantee