A series or reality show about OnStar operators and the people they help during the course of a day would be a good idea.
A study of gender and rock and roll and long-term popularity. Why no female Rolling Stones? It's a good and interesting idea. The GoGos don't count. Chrissy Hynde does.
When I'm on the phone where someone can hear me I think it's a good idea to say, "Look, man--I said I was clean." Because it's funny and makes you seem mysterious and persecuted.
A science fiction story or movie about Macbooks and how the camera is really always watching you, even when you don't have it turned on. Admit it--you worry about it and you know it's a good idea. This would be more than just I, Robot. (It would probably be a good idea to still have Will Smith's naked body in it though.) The book version of this could replace Fahrenheit 451, which I just can't take seriously now that we live in the actual future it predicted so lamely. (It's probably not a good idea to say that, but it's how I feel.)
It would be a good idea to send an e-mail to everyone clarifying that "interior decorating" is now known as "design."
It would be a good idea to write a novel about the Mormon Tabernacle Choir. It could uncover the seedy underbelly, expose the desperate housewives of MoTab, or it could be non-fictional and uplifting and end with Sting converting to Mormonism after singing with them in the tabernacle. (This could also be a reality show.)
An hour-long special where the Dog Whisperer and the Super Nanny trade places for a day. This is probably the best idea, ever.