http://vimeo.com/7675428 I've been experimenting with a cheap macro contraption. Generally, a dedicated macro lens works best. Next up is a screw-on filter style. After that is mounting two lenses end-to-end and lastly is my solution: just putting the lens on backwards. A mounted my Canon 35-80 1:4 on backwards and it worked...shockingly. The image is nearly impossible to control as the subject practically needs to be touching the lens and something like the 500D (linked above) would be much more practical, but this was a fun experiment.
Check out a few more images and a video of a $20 close up after the jump.