Everyone loves a good garden, but hunching over a pile of dirt to plant all of your seeds isn't much fun. If you want to take some of the back bending out of the equation, this PVC seed gun should do the trick.
ThinkMan's Blog shares the tutorial for this clever contraption. You'll need to cut the end of a PVC pipe into a "V" shape to dig into the soil, and close it off with a retractable metal flipper. Once you're finished, you can drop a seed or two in a funnel at the top so they slide down the pipe, then just pull the trigger to open up the flipper and release it into the soil. This is probably over-engineered if you're just planting a small herb garden, but it's perfect if you have a bigger yard and want to do a little more landscaping.
A Homemade Seed Planter [A Geezer's Ramblings]