From KCWC you could be easily led to this flickr stream where you may find other sites running similar challenges and some dedicated solely to boys clothes. I love the look on Elijah's face when I finish a project - even if it's not very good he will love it and wear it straight away. All of the fabric used came from either my sister (she knows all the best factory shops!) or I've had it sitting in my stash a while.
So you want to know the best places to find inspiration for boys clothes? This is a short list but I'm sure you'll find there is a number of blogs following on from these that may be of interest.
Well that's a start but there are literally hundreds of tutorials and ideas for boy's clothes - it just takes a little research.