> I think Sony would insist on owning anything you produce should they want it
When I was programming games for Sony in London ( about 5 or or so years ago, in the days of the PS1 ), I was also helping develop a board / card game for a local company ( http://www.dealmein.com, the “Game In Progress” section will give you a good idea of the game: Scrabble ( everyone knows this game ), with Cards ( language independant ) )
Before I signed up, I spoke to them about the game, how it wouldn’t be similar to the work that I was doing, and how it wouldn’t affect my working day ( ie too many late nights at the computer ), and got an additional, simple clause in my contract to cover it’s development.
It’s best to be up front… if it’s something computer related that you have an interest in, then it can be a good thing. If it’s something that could be considered competition in the future ( eg working for a Physics middleware company, and also helping with coding the open-source ODE physics engine) then it’s probably less of a good thing.