A clique at my high school where everyone is overly happy with no problems. They constantly say "YAY US!" "EEP!" "I WIN!" and so forth. People normally use it as a derogatory term because many flower power members are very annoying.
1. "oh look there's flower power. great." (used as sarcasm)
2. one of the flower power members--"OMG look it's a pop tart. bzz! yay! yay! my pop tart is better than yours!"