Quake 3 for Android
Kwaak3 and Kwakk3arena (xda forum thread) are ports of Ouake 3 to Android that looks interesting but do first person shooters really work on mobile touch screen devices? That’s one of the downsides to getting rid of the keyboard, but you could always connect a USB keyboard to your device. All you’d be missing is a mouse then!
I might get my old Quake 3 box out of the attic and give it a go, just to see it in action!