Last year our team did FRC lite with Capture the Flag. We worked with another local team and designed a game where a 3x3x3 foot cube held a flag pole top center, set 6" deep into the cube surface. The pole was a 1.5" stick of pvc pipe. The goal of the game was to capture the opposing team's flag and return it to a trash can on the other side of the center field line. Robot rules were basically the same as 2014, with max perimeter, weight, height, bumpers, starting configuration, etc. We had a six week design and build season and finished with a competition. Here's a highlight video:
https://youtu.be/3aahoGNRPow
We didn't really take to make time to develop the game or write the rules; we just reused the 2014 manual and changed the game, so that students could familiarize themselves with FRC manual reading.