This is from Knit One, Felt Two - Pattern is Classic Cloche, Adult Large, with Lamps Pride, worsted weight, in Black. I have added blocking / felting information at the end.
Post-felting (on the same table with the same rulers for size reference)
I used basic felting instructions and a zippered pillow case from my dear friend Sue. I pulled the hat out of the wash after two full cycles (note that I made another hat for a friend, using Paton's Classic Merino Wool and it only took a little more than one cycle of 16 minutes - so, check the hat periodically).
Here's a picture of what the hat looked like when I took it out. My hand is for size reference:
Next, I used a 1.5 Qt mixing bowl to shape the hat - the bowl helps to make sure the hat will be consistently round and smooth all the way around. As you may or may not be able to tell from the picture, the bowl is about 7 inches in diameter.
I put the hat on the bowl and rolled up the edges. I did have to do a bit of pulling on the edge to get it to stretch out a bit. Otherwise it will just go straight down (hey - this may be what you want, but I want mine to flare out a bit):
Next, I left the hat on the bowl until it was dry enough to hold it's shape (a few hours). Then I put the hat on top of a heating vent and let it dry completely. You will want to put the hat on something where it can get some air under it - you can even use a cooling rack, or a rack from your oven. This will help it dry faster and more evenly.
If your hat should happen to end up too small, you can throw it in the sink, rinse it down with some warm/hot water and stretch it out. This may involve putting the hat on your head - so be prepared to ruin any hairstyling you've done. If the hat is too big, you can simply throw it back into the washing machine and let it felt some more. Be sure to check any felting project every minute or so to prevent over felting. Once those items start to felt, the generally do so very quickly.