Alex and Izzie got married in "What a Difference a Day Makes," the 100th episode of Grey's Anatomy. It was a great scene and a great episode.
Added:
That was the climactic scene of the 100th episode of Grey's Anatomy - the surprise nuptials of Alex and Izzie. Meredith and Derek were the ones supposedly getting married this day!
Added:
Izzie and Alex kiss after exchanging vows in their emotional wedding. The whole gang was on hand to watch the two doctors get married.
Added:
Alex and Izzie embrace after getting married in "What a Difference a Day Makes," the 100th episode of Grey's Anatomy, from Season Five. It was a great Grey's moment, no question about it.
Added:
Alex and Izzie tie the knot on a very special Grey's Anatomy. They're all special, but this was one for the ages.
Added:
Alex sweeps Izzie off his feet by reciting the wedding vows he made up after being inspired by a patient's planned valedictory speech. Truly touching.
Added:
Alex wows Izzie with heartfelt wedding vows.
Added:
Cristina and Meredith talk to Izzie before her wedding to Alex. This episode, the 100th, was one of Grey's Anatomy's best in recent memory.
Added:

Grey's Anatomy Quotes

When we say things like "people don't change" it drives scientist crazy because change is literally the only constant in all of science. Energy. Matter. It's always changing, morphing, merging, growing, dying. It's the way people try not to change that's unnatural. The way we cling to what things were instead of letting things be what they are. The way we cling to old memories instead of forming new ones. The way we insist on believing despite every scientific indication that anything in this lifetime is permanent. Change is constant. How we experience change that's up to us. It can feel like death or it can feel like a second chance at life. If we open our fingers, loosen our grips, go with it, it can feel like pure adrenaline. Like at any moment we can have another chance at life. Like at any moment, we can be born all over again.

Meredith

Did you say it? 'I love you. I don't ever want to live without you. You changed my life.' Did you say it? Make a plan. Set a goal. Work toward it, but every now and then, look around; Drink it in 'cause this is it. It might all be gone tomorrow."

Meredith (closing voiceover)