A couple of years ago, I went out with a group of friends for dinner and drinks. At the end of the night, a guy that I was interested in told me to give him a call "sometime." I called the next afternoon and was invited to his house for dinner that very night. I accepted the invitation, and we had a great time.
We got married a month ago.
Moral of the story: If the guy really likes you, then he won't care when you call.