Here's a simple yet ingenious idea from
Real Simple for dealing with any nasty sunburns.
Simply pour some aloe vera in an ice cube tray before sticking it in the
freezer.

Make sure you use real aloe vera from the grocery store since most aloe applications are really moisturizing lotions that may not freeze very well. Once you have some, you can either mix it with water, or pour a good amount into each section of the ice cube tray, and toss it in the freezer overnight.
So the next time you go out into the sun, at least you'll have a soothing and chilling home remedy to apply to your burn once you get back inside.