Mini Sniping. Simple but addictive game that will kill hours in the backyard, especially when your shooting buddies come by.
Here is a whole link to the game from a long ago friend in the Field Target Competitions.
http://www.minisniping.org/Todays guns, especially the ones for Field Target, will make this pretty easy. It's best to stick to lower velocity, but scary acuarate guns that the wind will have more affect on.
Originally made for spent 9mm cases, it is no problem to scale the target size down or change the distances to suit your capabilities and equipment.
We've done it with targets as small as toothpicks. Sweet Tart candies are fun too cause they blow up when you hit them!
Read through the link and use your imagination to modify it to your own way.
Have fun!!
And if it's just too bad to get outside you can always read the Capstick books!