When Mike gave his keynote (.ogg) at FSOSS 06, he emphasized the fact that "small is beautiful" when it comes to open source contributions. It's a very inviting message to those who are just starting out, and one that I've often repeated to my students as they get started in the largest open source projects. But is it true? Survey says...'yes'.
"...the most common size of code contributions is one line of source code. Of all commits in our more than 8 million strong sample, one-line source code commits represent more than 12%, two-line commits represent 9%, and three-line commits represent 5.5% of all commits."
I still remember the day Tom submitted a patch that added a single space (which needed several levels of review!), in order to get his patched distcc to work with the Mozilla tree. It was the most beautiful space I'd ever seen, and I've seen many :)