There are few that comes to mind.
Bangladesh vs Bermuda, 2007 WC. The rain effected WC match, was a real tricky one but thanks to Sir Ash's 20 odd something, we won. Everyone was falling except Sir Ash. Felt relieved. Because had we lost that, the victory against India would have meant nothing.
Bangladesh vs England, 2011 WC, I was just counting the number of runs reqd every minute. And when we won, I was in tears.
Bangladesh vs India, 2012 Asia Cup. All hopes were gone after Tamim's wicket. But enter Shakib, and he completely changed the momentum. From then on, I kind of had faith that Mushy would see us through. I was so ecstatic. I was watching this with a bunch of Indian friends and shouted FU on their face.
Everyone patted me on my back. And the number of phone calls I received saying they'd support BD in the finals, it was exhilarating!