I've been wondering why we haven't yet seen where a game developer takes a leading FOSS game and adds bitcoin mining functionality into it.
Or, take an open source game and add a Bitcoin-related angle to it (i.e., monetize it using Bitcoins).
From the following: http://gaming.mozillalabs.com/games
is the open source browser game "Marble Run".
The site which the game is built for provides a "special brick" randomly to visitors, at periodic intervals. Simply adding the ability to purchase a special brick with Bitcoins would be one way to monetize the game.
I learned about the site from the author of a closed-source game called FavIMon which is a Pokemon inspired game: http://www.favimon.com
in which the author was asked if the game could benefit by incorporating Bitcoin: http://twitter.com/philipnrobbins/statuses/45106745743392768
FavImon and Marble Run are among the Winners of the Game On open Web dev competition: http://mozillalabs.com/gaming/2011/02/03/game-on-winners/
With no software to install, games like these could end up being responsible for the first exposure to bitcoin for many.