Don't have much space to grow your favorite plants? Try building a vertical garden like this one, designed by Susie Frazier. Using salvaged wood, threaded rods and bolts, and a handful of mason jars, you can construct a simple hanging planter to add a lot
How to: Make a Modern, Space-Saving Vertical Vegetable Garden
DIY Yarn Wrapped Jam Jars - it's a good idea for the tunnel just to light the way. A solid row of these along the sides of the tunnel would be a good alternative to using whatever lights are built into it.
Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.