Adanaxis from Mushware is one of those first-person zero-gee interstellar space shoot 'em games.  You know, blow up the other fleet, protect the convoy, etc, etc.  The physics aren't real flight physics: you go as long as you hold the button down, you stop when you let it up, there's no acceleration or momentum.

There is, however, flight through four spatial dimensions.  My attempts to explain aren't working very well at the moment, so I suggest you just go download the demo.  (Or watch a gameplay movie.)

Found on http://happypenguin.org.  available for WinXP, OS X, and Linux.  Shareware.