At the recent Wearables tech event in London I notice a group of young people noisily enjoying themselves at the illuminate apparel stand. Closer investigation showed that they were having great fun writing in light on a phosphor coated t-shirt. It was great to see apparel being such fun. On the one level this idea is straightforward, others have played with Phosphors on shirts. In this case they have taken things further, devising a phosphor that is more intense and long lasting, combining this with a simple LED writing device. At one level this could be considered gimmicky, however that would be to miss the point, what we have here is playful apparel, one that you and friends can experiment with.
In low-light doodles on the shirt persists for a surprisingly long time.
Source: Illuminated Apparel