Every year, I like to carve a mini pumpkin to decorate the center of my dining table. Mini jack-o'-lanterns are always so darn cute, and many people don't realize that mini pumpkins can be carved just like normal-sized pumpkins.
I often carve the top in a square shape. When working with a pumpkin this small, it is easier to cut in straight lines versus curvy ones.
Then, I like to use a melon baller to scrape out the inside of the pumpkin until it is clean. Melon ballers can usually be found pretty inexpensively at thrift stores.
Once cleaned out, I use the smallest knife I can find for cutting the face. This year, I had a small saw from a set of pumpkin carving tools I found at Williams-Sonoma, but in the past I've used a steak knife or X-ACTO knife. I've found out that X-ACTO makes small keyhole saw blades as well, and I think these would work beautifully for this purpose as well.
Usually I light the mini jack-o'-lantern with a battery-operated tea light candle. DO NOT USE A REAL CANDLE: the flame will cook the top of your pumpkin. Mini pumpkins are just too small for a real fire.
Have fun with those mini pumpkins!