Stressful, even though I've been to many other interviews before. All candidates were brought in the same room and made to work together and achieve a puzzle-like challenge, using some kindergarten toys/geometries. 5 or 6 employees would observe and grade them (HR, hiring manager, future colleagues etc). Who thought of that strategy, must have not taken into account that those future colleagues that felt had a say in the hiring process might "bet" on another horse, but would end up with someone else as colleague.