If you're near the Ohio/Indiana border, do yourself a favor and stop for a meal at Ahi Chihuahua, a fantastic Mexican restaurant (and grocery) in the center of Angola, Indiana (25 minutes south of Interstate 80, near the eastern border). A friend and I accidentally stopped there once; they serve some of the best Mexican food I've had anywhere. Everything we ate was excellent, but the highlight was their bizarrely delicious salsa, unlike any other we'd eaten before or since. We nearly made ourselves sick eating a quart of it. The owner's daughter wouldn't give us the recipe, claiming that her father didn't even know it. We bought a container to take home to analyze, but left it in the car overnight, spoiling it.

When I moved to PA from IL, I stopped at Ahi Chihuahua for a second time, and bought more salsa, and even managed to bring some home safely, but wasn't able to figure out how to duplicate it before consuming it all.

Update 27 July 2005
When I moved to Chicago earlier this month, I stopped once again. It was as amazing as ever. Here are the Mapquest directions:

From I-80 W:
1. Take EXIT 151B toward BLOOMSBURG (Portions toll).
2: Take the OH-49 exit- EXIT 2 / 1. 0.3 miles
3: Turn RIGHT onto OH-49. 0.2 miles
4: Turn LEFT onto US-20 W. 12.1 miles
5: Turn RIGHT onto S WAYNE ST. <0.1 miles
6: End at Ahi Chihuahua (200 S Wayne St, Angola, IN 46703-1937)