I think that you can get Tribes Beta Keys by liking them on Facebook right now, not sure. If not, I do have a spare I can hand out! I got a key from Rock Paper Shotgun, but I paid the $30 within a couple hours of trying it. The nostalgia factor for me is through the roof. It's a bit modernized, yes, but it's still got enough of the old jetpacky, shazbotty goodness to make me love it. I also really like the class system, even though I don't really go for the F2P model too often (I think my "I want to try everything" playstyle wouldn't work well if I hadn't paid up).

I can't speak much for MK since I haven't played it and don't usually like fighting games too much, but even in beta for Tribes, I'm having a blast. I had completely forgotten how great it is to "duel" someone in a FPS, particularly when it's a jetpack-based dance at a couple hundred miles per hour. You just don't see that in shooters these days.

I think I had the same problem and I have a pretty good idea of what causes it. The 360 knows if it's lying flat or on its side, and the lights rotate to reflect which position it's in. The blinking light is caused by the 360 getting confused about what side it's on. Mine is usually on its side, so I turned it flat, then turned it back. I haven't seen the same problem since.