With the Halloween holiday approaching, Twilio is hosting a contest where developers can create innovative apps using their platform. Ideas include building voice broadcast apps to send Halloween wishes, integrating phone numbers into costumes and jack-o-lanterns, creating creepy voicemail messages, and setting up neighborhood phone trees for kids' safety. The contest aims to showcase the possibilities of Twilio's APIs and SDKs in creative ways, and developers are encouraged to submit their submissions early as they will be featured on Twilio's blog.