PC World magazine put together a short tutorial on recognizing eleven common email scams. Each page includes an actual example, most culled from recent messages being sent out by the notorious Storm Warn gang, a group of hackers based out of Germany who not only run the scams themselves, but also sell their hacker toolkits to others.
Some of the scams seem pretty obvious (like number 10, the IRS scam) but others are very sophisticated in their tactics such as number 9 where the hacker is impersonating an indignant eBay customer accusing you of not responding to his question or number 11 where the hacker took the time to personalize the attack based on the victim's alumni listing.
Number 5, the NFL stat-tracking software, is particularly effective because the webpage is so professionally done. And there really are some good free software programs out there. (Well, not completely free since they're ad-supported but for an avid fan a few ads might not be too much to pay.) The problem is that there are a few very dangerous landmines hidden among the legitimate tools. Short of completely rewriting the code yourself, there is no way to tell the safe ones from the scams.
Never download "free" software unless you are completely sure of the reliability of the source and never load any software onto your work computer yourself. Always call your IT department.