If you want to make random people randomly happy, start blowing bubbles. By the way, seeing them happy will probably make you happy. Who knows, they may even thank you!
Oh and guess what? I'm getting an iPhone this evening. I am quite happy, and still amazed that mom is actually getting me one. She decided to get it because it should help me stay on top of things. So I'm figuring I'll put all kinds of alarms on it, reminding me what is due when.