Hacking Systems

So what success stories do people have from taking bits and pieces or components from different games and putting them into others?

Has anyone done this for AD&D, Shadowrun, Storyteller or other games?

I used the Cyberpunk 2020 lifepath for an Old World of Darkness campaign. Worked perfectly fine. All I had to do was change all the "+2 to x skill" to "+1 dot to x ability".

Mind you, I tend to take ideas from games rather than mechanics.