Twilio has joined forces with Etsy and Dwolla to host the eCommerce Hack Day in New York City on August 4-5. The event is open to developers who have already registered, while designers can still attend the demo session. To encourage participation, Dwolla created a puzzle in the hackathon's website source code that the first 200 developers who solve it will receive a free ticket. Various mashups using Twilio and other sponsors' technologies will be showcased during the event, including Dollar Thoughts, Anonysize.me, Custard, and Cone Patrol. Interested individuals can follow @EcommerceHackNY and #eCommerceHackDay to stay updated on the event.