This needs to come back. URF Random helped make it better, but other than that there are no fun game modes that are in the rotating game modes que.
Ascension got really old, really quickly, One weekend and I was done.
Hexakill Twisted Treeline wasn't very exciting and the meta made certain champs unplayable while others you kept seeing over and over again.
Doombots honestly was really disappointing, I didn't have as much fun this time around as I did the last.
Legend of the Poroking - It's nice to be able to choose a champion in Howling Abyss, but I miss not being able to have certain summoner spells.
All for One - WOULD be decent but not everyone's vote is equal. I don't really see the point in playing a game mode where I have literally no chance to get a champ I want to play, and have to rely on others tastes to have a decent chance. I don't mind not getting a champ I want, but having a CHANCE to get a champ I want to play would be nice.
Nexus Siege was but it always felt one sided, the match making felt terrible.
Black Market Brawlers was fun. It offered that Summoners rift feel but with some added fun. Not only that but its free R+D. Toss items out each time, hell send some wacky items that might never see the light of day. It was fun because you could get items you couldn't normally get, and those little brawlers were fun and added to the experience.