Bull Frog Sunblock is amazing. I just happened upon it at a drugstore once and grabbed a bottle only to find that it seems to work better than any other. In 100 degree temps I can put it on once and be out in the heat all day and never have to reapply. The only thing that bugged me with it is that you do need to wash your hands well after application or you can get it in your eyes easily and it burns pretty good. In fact, I don't care much for putting it on my forehead as it seems to mix with sweat and can get in our eyes easily that way, too. They've got a new "stick" out that may help that, however. It's like a larger "chapstick" type tube. This should be great for applying block to the faces of your kids.
Sunburn isn't just aggravating. It can definitely lead to skin cancer. Use sunscreen. You have been warned. Dang, I'm full of warnings today.