We have all used Comic Sans font in our early days. Though its considered more of a joke now but it certainly has a novelty factor attached to it. Comic Sans Font Creator, Vincent Connare talks about the need to create the font. Its a good read.
Comic Sans was designed because when I was working at Microsoft I received a beta version of Microsoft Bob. It was a comic software package that had a dog called Rover at the beginning and he had a balloon with messages using Times New Roman.
There was no intention to include the font in other applications other than those designed for children when I designed Comic Sans. The inspiration came at the shock of seeing Times New Roman used in an inappropriate way.
Source: Vincent Connare’s Blog.