I made my newest one a pumpkin hat for the season. It was a very simple pattern, except for the leaf, and it knitted up in one evening. My older boy loves it but it's too small for him and I think he looks a bit weird in something that looks so baby. I used this pattern:
I highly recommend it, extremely easy pattern with great results!
I used a chunky orange yarn with brown wool for the stem and green dishcloth cotton for the leaf.