Sabagebu! Survival Game Club!
While on her way to her first day of high school, Momoka Sonokawa has an unpleasant encounter with a wayward train pervert. But when a gun-wielding girl named Miou comes to her aid, Momoka soon discovers that not only does she go to the same school, but she happens to be the president of the Survival Game Club! Soon, Momoka finds herself sucked into joining this club full of weirdos and participating in their questionable events.
[Source: Sentai Filmworks]