My 1999 Civic won't start
 

My '99 Civic sat in the garage for 2 weeks without starting. When I
tried about half an hour ago to start it, it simply didn't start. The
battery seems OK as everything that needs the battery works properly,
including headlights.

The car was starting perfectly before I left it for this 2 week
vacation, so I am puzzled as to what could possibly be the problem.

Any ideas where and/or how to start troubleshooting?

Thanks,
Sam