Here's my favorite idea - it'll probably never happen, but I give it to the universe via the O-Deck, in hopes that I might one day get to play this game:
The working title for the first game is War Bird. You play the character of Kerouac, a pigeon - bear with me, now - who has grown up as a "clinker" or street pigeon, flying the mean alleys and rooftops of Depression-era New York City.
The first part of the game is a coming-of-age story as the fledgling Kerouac trains to become a "flight" - developing advanced aerobatic skills as a champion homing and racing pigeon. A major part of the game is the conceit that pigeons have their own culture (think Watership Down), communicating telepathically in their own language, which is influenced by beat poetry. There's gang-like rivalry between different neighborhood coops, youthful romance and a mentor/student relationship between Kerouac and an older pigeon who inspires him to "fly higher".
Basically, it's a character and story-heavy game with action elements; because the pigeons have no real offensive capability, the action emphasizes strategy, stealth and evasion over direct combat. I envision the dialog being written by poets.
The second part takes place after the outbreak of WW2. Kerouac is "drafted" as a war bird, joining the US Army Pigeon Service and undertaking dangerous reconnaissance and communication missions across no-man's land. The game ends tragically, but heroically.
Well, there it is - possibly the least commercial concept for a video game, but I'd love to play it.
Feel free to add comments or questions, or to outline your own "dream" game(s).