Using the OTG CABLE and a 4port usb hub. I was able to charge my nexus 7, connect a wireless keyboard and mouse, ps2 controller and 16 Gig USB key.
Here is a link to the USB HUB:
Newegg.com - GearHead UH2100 4-port USB 2.0 Hub with Integrated USB Cable
I ordered another ps2 to usb cable so I can try to play the NES game "Contra" Emulator. In two player mode. (I'll update everyone on my progress.)