This past summer I removed the light bulb and housing around my yard light. This is a yard light that stands on a post and is required by the local homeowners association rules. I replaced it with a solar powered light that has a little charger on top and it charges up all day then comes on at night. I love it, although it is not quite as bright as most of the traditional light bulb yard lights in the neighborhood.
I have noticed in the past few months that some other people have replaced their electric yard lights with solar power as well. The price of this stuff has come down and the quality improved.
So, yesterday I used solar Christmas lights for the first time. I decorated a Saguaro in my front yard [that's a big cactus for you Gringo types]. The lights came on at dark and work great. And I did not have to run extension cords and timers around. I just wrapped the cactus and placed the power box near the base and let it do its solar thing.