[Taylor]

I'd make an argument for 2009-2012.
Lunacy was a game that had a cool theme, accessible game objective, useful human players. Very simple pump-and-dump robots could be successful, and the Fullest-Trailer-Loses concept made it easy to track.
2010 featured an easy to explain game with a bit more mechanical sophistication. Still accessible to BLTs, rewarding and exciting for more elegant designs.
Logomotion was a cool celebration of FIRST; an easy to understand and score game; exciting and impressive to watch great matches.
2012 was, in my eyes, the GOAT game. A fantastic way for a student to end his/her high school career. Exciting gameplay, exciting endgame, balanced scoring, not too penalty-ridden, plus the concept of the Coopetition Bridge was a great way to bring in people new to this style of robotics competitions.