Watching TV as a kid, with your nose pressed up to the screen, celebs on American Idol looked larger than life. Well, for kids at Ronald McDonald House New York [1] yesterday, they actually got to see Idol celebs, life-size.

David Cook, Constantine Maroulis, and David Archuleta stopped by the charity that provides a home away from home for children with cancer and their families.

"Now that I'm a young Dad, being here is so important," Constantine shared with DoSomething.org after his rock-heavy performance. "You can affect people through art."

And affected they were. The crowd went wild for the performances, especially David Cook's.

"I'm very passionate about cancer research," explained Cook, who lost his brother to brain cancer. "You don't need a platform to do a great thing. Just donate. Volunteer."

David Cooke and Constantine's edgy sounds were contrasted with David Archuleta's soulful renditions of songs like "1000 Miles" by Vanessa Carlton.

David and the other guys had a chance to meet the kids of the house earlier in the day, and we wanted the pop star's advice on how to break the ice when volunteering with kids.

"Get to know their names. Get to know their personalities," Archuleta advised.

If you feel a little nervous about helping kids in person, you can still make an impact. Register as a bone marrow donor [2] for the chance to potentially save a kid with Leukemia or other blood cancers, or text DoSomething to 38383 to receive updates on how you can take action any time of year.