Additional thought: I may modify the code to make this a "real" project. All I'd really need to add is Serial input (to "record" the message) and store the messages in flash so it retains the data during poweroff. That way you could connect via serial (even terminal program or serial monitor in IDE), dump in your message, and be ready to go.
LED blinkies are popular in the colleges around here, I think making a simple NTSC video text generator that is essentially disposable might have some really cool Guerilla Art potential.. probably best to create a markup language for the input, so that delays could be set, inverts could be done for effect, and graphics could be incorporated.
Last but not least, as long it meets the memory required and can be clocked at a workable rate, I would assume this could be ported over to even smaller, cheaper Atmel chips like ATTINY. Just how small a package could you fit 4x button cell, ATTINY, and a RCA plug into?