Car trouble

Driving home from picking up a redbox movie, my husband noticed a loud tick, tick, tick, tick...coming from the engine of our 2000 Suzuki Grand Vitara. We've had this car for over 7 years, and it's been terrific, with very few major repairs. We spent good money a few years ago to get all the regular maintenance up to date, prior to a 300+ mile trip up to the north shore.

Smart man, he picked up a couple quarts of oil on his way home tonight. How can the engine not have any oil in it? Really? I'm finding out all kinds of answers on About.com auto repair pages. I love the internet.
Hopefully the oil addition will fix it, and the next regularly scheduled visit to the mechanic will be more educational and hold us over for a while longer. If it turns out to be lots more, you know I'll keep my Facebook friends posted.