A few years ago, my family gathered in Mississippi for a funeral. While we were there, we undertook the renovation of a living area and found it was quick and easy to make some energy efficient choices. We replaced all of the regular light bulbs with compact fluorescent bulbs (CFLs) wherever practical and installed timers for lamps in the family room.
The changes stuck. The home owner still uses CFLs, having replaced one or two of the bulbs since then, and the timers have come in handy. The amount of energy saved isn't insignificant either, with the (small) investment having repaid itself several times over.
These are things you can probably do for yourself, but think about doing them for a relative. Do you have parents or grandparents who might benefit from some energy efficient kindness?
Buying CFLs is something you can do today. Replace their light bulbs and it's probably the last time they'll have to think about this chore for years to come.
If you're comfortable with a caulking gun, touch up the caulk or weatherstripping around their windows—especially if you can feel a breeze from any of them. It's not just energy efficient, but it could help keep them from getting cold during the winter.
Consider doing them a "random act of kindness" by making their home more energy efficient. You're not only saving them money, you're showing them how much you care.