There's pumpkins that you can get that float around the site. What are they for?

If you click on them, they get added to your inventory, where they can be carved or fed to your pets.

There are also achievements for carving a certain amount of pumpkins. (I'm not sure what the exact tiers are; maybe 1, 5, 10, 25, 50? :s )

Edit: Nevermind.

has a pretty good method. i use that as well. sometimes i just put them in my shop and sell them after i have carved them..its really whatever you view is the best method for you