Nowadays it seems to mean eating tofu and attending yoga classes. Having a Hindu Guru stay at your house whilst he tells you what to do and eats all your food makes you doubly open minded.
Don't forget to be sipping green tea while you're doing all this, Pineapple!
This is an excellent question, MahoganySnail, and I agree with the posters who say there has to be a balance between acceptance and discernment.
I was reading a Christian book a while back (sorry, can't remember it exactly...) and the author said it was great to be open-minded, but not SO open-minded that your brain falls out every time you lean over! I've been guilty of both extremes and am trying to work on the balance!
I also think being open-minded should mean not pigeon-holing or stereotyping people and approaching everyone you meet with a fresh slate. For example, I was recently chatting online with a very nice guy who'd had a girlfriend who was half Korean and another Korean female friend, so he was saying things like, "I bet you... do this or that, think such and such way..."
I tried as politely as possible to say, "Well, if you get to know a little about me... I think you'll find I'm my own person and it sounds like I'm a lot different than your ex-girlfriend!"