Initially came across this fun list via Twitter:
His actual post, is embedded in his Tweet, but you can visit the list here. But in particular I enjoyed #8:
Turn open source projects in to SAAS businesses — Find open source projects that are very popular and turn these in to out of the box services for enterprises, e.g. PagerDuty is like Nagios.
Great entrepreneurial advice, and easily serves as a fun jumping-off point for any viable hack-a-thon. Any hacker or eager founder can find some amazing open-source projects and inspiration on Github.
My personal favorite startup adage, for any would-be-founder is, be the arms dealer.