First Tibes game I played was a PS2 version my dad had, called Tribes: Arial Assault.
While I never got to play that game online I wanted more. I didn't have a PS2 at the time so I went to the internet and found it was a PC game too.....
After that I have played every Tribes game made, and think almost all of them (F2P Ascend being just ok) are defacto classics.
Also the mods for new characters, just like UT, where amazing.
Videos of 1,2,3
Free to Own
In a rare move of good will all of these are free, located here, from Hi-Rez it self DRM free (except Ascend)
Yes this includes EarthSiege, I will get to that eventually.