Most of the Nigerian scams are obvious enough - if it seems to good to be true it probably is. The latest one is particularly nasty and could easily catch you out.

The email purports to be from a friend stuck in Africa while on an unannounced mercy mission. The email address is your friend's and if your friend is inclined to this sort of behaviour it may seem plausible.

The reality is their email account has been hacked and the password changed so they can't get in. Whoever has made it in will take full advantage of any email addresses they find.

The email goes:
How are you doing today?
  I am sorry I didn't inform you about my traveling to Africa for a program called "Empowering Youths to Fight Racism, HIV/AIDS and Poverty. The program is taking place in three major countries in Africa which are Ghana, South Africa and Nigeria . It has been a very sad and bad moment for me, the present condition I find myself in is very hard for me to explain.
    I am really stranded in Nigeria cos I forgot my little bag  where my money, passport, documents and other valuable things are kept in the Taxi on my way to the Hotel where i am lodged, I am facing a hard time here because I have no money on me. I am now owing a hotel bill of $600 and they want me to pay the bill else they will have to seize my other bag and hand me over to the Hotel Management., I need this help from you urgently to help me back home, I need you to help me with the hotel bill and i will also need $900 to feed and help myself back home so please can you help me with a sum of $1500 to sort out my problems here? I need this help so much and on time because i am in a terrible and tight situation here.
    I am sending you this e-mail from the hotel's cafe and I only have 10 min to do so, I will appreciate what so ever you can afford to send me for now and I promise to pay back your money as soon as i return home so please let me know on time so that i can forward you the details you need to transfer the money through Money Gram or Western Union.
  My Regards.

Obvious enough unless your friend might just be in Africa and I suspect in many cases in NIACT there is just that possibility.