See: http://jsfiddle.net/b2BpB/1/
Q: How can you make box1 and box3 align to the top of the parent div boxContainer?
boxContainer
#boxContainerContai
Use vertical-align:top; for the element you want at the top, as I have demonstrated on your jsfiddle.
http://www.brunildo.org/test/inline-block.html