Taking input from a generic usb gamepad in controllers (preferably like MSP430g2231)
As the device is a "USB HID Device" then the system you want to build would have to act like a "USB Host".

For this you will require a microcontroller with "USB 2.0 OTG" in it (OTG = On The Go).

The little MSP430s in the launchpad don't do it.

You would need something like a PIC24 or PIC32 that has the facility, or one the Atmel chips with OTG in it.  There are probably some TI chips that do it as well, but not that will fit in the launchpad.

It's generally the higher-end chips that have that facility.