Hot off the back of Make Your Own Monopoly I discovered this Top Trumps site. Sorry Top Mates!
Its simplicity at its very best - turn photo's of your friends/family/pets into unique packs of playing cards. Decide which ratings to use, customisable categories and rock on.
You can also make a free sample online very easily and e-mail it to your friends.
The only thing you need are photo's in a digital format - they do everything else for you and hey presto a pack of very cool top trump cards tips up!
Warning the free generator is addictive!