Recently I was researching a potential scam (to avoid, not to commit, of course) and I came across this website, which lists a number of scams and how to avoid falling for them. http://scam-detector.com/scams The scams are organized by category and there's a search engine to make research easier. You can also share your own experiences with scams you've encountered. Some of these scams you can understand and others make you wonder who would fall for them. Some make you think, "You have got to be kidding me..."
I also have to add that if you're approached by someone claiming to be from a charitable organization, do your research before deciding whether or not to donate anything. You should be especially wary if a group doesn't want you to do research. One day a woman called me claiming to be from a charity which donates gift baskets to children suffering from leukemia. I had heard about scammers who falsely claim to help sick children (which is absolutely shameful, to say the least), so I told her that I wanted to do some research first. She told me that if I let her send me the information about making a donation, their website address would be included. She apparently didn't want me to think about the fact that their own website wasn't going to tell me whether or not it was a scam. I insisted that I was going to do research on my own before committing to a donation. I haven't heard from the group since, and sure enough, it turned out to be a scam.