Our class is too young to carve a pumpkin, so every year we adapt this activity and make it a sensory activity. We cut open the pumpkin and have the children reach in and feel the insides. This is a great opportunity for language too! Make sure to talk about the textures (slimy, wet, etc). Talk about what they find inside, count the seeds, etc.
After the pumpkin is cut open it will likely rot pretty quickly, so we usually just toss them out. However, this year we filled the pumpkin with dirt and placed it by the window. Once the pumpkin was filled we talked about what we thought was going to happen. Have students help water it every day (we used a spray bottle from the Dollar Tree, a great OT/fine motor activity).
My students loved charting the progress of the pumpkin and posting updated pictures of it on the wall next to it. This helped them to make observations and refer back to what the pumpkin looked like before.