Feng Shui, by Robin D Laws, is a perennially popular high action RPG set in a world of time travel, secret conspiracies and flying monkeys with chainguns. Published by Atlas Games, it's now in its second edition, co-written with Cam Banks. It is, for my money, the only multi-genre action RPG you'll ever need. It can run historical wuxia, contemporary gunplay or urban horror action with equal aplomb.
Most of the material here was written for the first edition. On one day I will go through it all and see what can be repurposed for the second edition, but it is not this day.
I wrote an entire fan supplement, Out for Blood, as a GM's guide. Again, it's for the first edition.
Download it here.
There is a whole bunch of stuff I wrote to assist the GM and players with managing to find content in all the first edition splatbooks. I also rustled up some miscellaneous additional rules, schticks and character types. I've rehosted them all on googledocs and linked them here.
This doesn't fit anywhere else and I don't want it to be lost to the ages.