[aballen] wanted to light the jack-o’-lantern this year with something that didn’t actually require fire. After searching for a project that was cheap and yielded decent results, he ended up just making his own. This project utilizes an ATtiny13 and two LEDs, red and orange. The overall build is quick and simple with some very basic code for the flickering. If you really want it more enclosed, there is this similar project using a cheap electric candle. Of course, not everyone has the time or desire to make one that is this realistic. You could always just go the easy way, no microcontroller required.
Why limit it to just lighting up your pumpkin though? Lets take a stroll through Evil Mad Scientist Laboratories hallways and see the Snap O Lantern or the dark detecting pumpkin and the Cyclonolantern.