As I learn about writing and the writing biz, I often come across references to "The Hook." You have to have one and it has to happen in the first line. The Hook is that somethin'-somethin' that makes the reader (agent, publisher) wonder, "what the heck is going on?" and "man, I have to find out."
I came across something that illustrates this perfectly. It's called Twitterlit. It's a blog (affliated with Amazon, quite clearly declared in the sidebar) that daily posts the first line only of an unnamed book.
"The human head is of the same approximate size and weight as a roaster chicken."
Makes me want to read, how about you? If you so feel compelled, you click the link which takes you to the book on Amazon. (That one was Stiff by Mary Roach).
It's an interesting idea. I think every reader has a favorite first line. Mine is "Last night I dreamt I went to Manderley again." Anyone know it? What's your favorite?
There are even online quizes dedicated to the first line. Here's a fun one.