Okay, so this ventures into the realm of the off-topic, but not really. I had a bit of spare time this week, so I thought I'd have some fun:
Find a baby. This was easy for me because my wife just had this one on January 1st, 2008. Hooray for us!
Buy an inexpensive "onesie", as they are apparently called by people who buy such things. This one was cheap enough that I could ruin it if I wanted to. (note to self: wash and dry these first so that they've already shrunk before doing the transfer)
Buy some heat transfer paper for an inkjet printer. I found this at one of those big office supply chain stores.
Draw something resembling armor. In this case, I shaped the armor to hopefully look good on a baby. I have no idea at this point how much detail is going to come out. (There's a larger png attached to this post, for those who want take a closer look)
Print out the pattern on the transfer paper, mirrored so that it's the right way when facing down on the fabric. The pictured paper was a test print, apparently my yellow toner was dry. The real thing turned out well.
Cut out the transfers, and iron them on the fabric per the instructions.
Wash and wear, applying Star Wars nerd stigma to your child, well before he has any say in the matter. The look on his face in the last pic says it all.
In retrospect, this might have looked better on a light blue outfit, but I was concerned that the yellow shoulder armor would look green. Fortunately, he'll outgrow this outfit in a week and I can try again.