Winner (699 teams) · Cal Hacks 12.0 · Oct 2025

The team arrived at the hackathon with nowhere to sleep, so they built phone bots that called more than 100 real hotels overnight to haggle. By morning they had talked a luxury room down to $158.

Why it won: Everything in the demo was real: live phone calls, real hotel clerks, real money, and the team actually slept in the room that night. The hard engineering was keeping an AI steady on a live call, answering instantly without freezing or making things up while a human waits on the other end. Most projects like this get shown as a recording; this one ran on real phone lines where anyone could say anything back.