My piece, 503558666, is a phone-based experience, mixing modern corporate culture, contemporary art criticism, and classic choose-your-own adventure games.
Creating it was grueling -- overall, it has over 60,000 words, including narrative branches that are only accessible at certain times, by certain people, or purely by chance. But my intention was to have a depth of interaction that contradicts the flat, minimal visual presentation; so I really needed to push the content. I'm glad I found a good text-to-speech system, because attempting to record all the narration would have been insane.
The piece evoked some interesting reactions. Some didn't know it was a phone number to call, some chose not to call at all. Those that did spent anywhere between a couple of seconds to 47 minutes of time with it.