We paired up enemies in “Rivals” and old flames in “Battle of the Exes,” now we’re going old school. “The Challenge: Battle of the Seasons” reunites cast members from some of the Real World’s most memorable seasons. Within each team, there are exes, rivalries, current romances, best friendships and everything in between that could either help or hurt them in their goal to become the last season standing. And to make matters more intense, in competing for $350,000 in grand prizes, the former roommates may have to turn on each other to secure their own safety in the game. The usual struggles of strength and stamina will remain, but this time, they’ll have to sort out their issues from their original season if they want to win it all.