kalabunga
You yell it when you're so happy you think you're going to explode. Like a tiny human fireworks show.
Kalabunga! I got a 100 on my math test and my dog did a backflip!
Kalabunga! I just got free soda and my friend said I look cool!
Kalabunga! I spilled my coffee on my teacher and now I'm famous!