I stumbled upon this series while looking for new manga to read, and it's gained a small following from people on other web sites I've discussed it with, so I thought I'd spread the word here.
Basically, the god of Deus Ex Machina alters the diaries of twelve people so that they contain entries about future events. They have to use this information to find and eliminate the others, or when trapped in a sequence of events leading to their death use their knowledge of the future to change events and escape a BAD END.
The best part of the series is probably the heroine of the series, because she's a psycho yandere who stalks the main character and doesn't give a second thought about killing people who she sees as a threat to him or their love.
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn004.jpg (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn004.jpg)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mirai_nikki_002.png (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mirai_nikki_002.png)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn015.png (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn015.png)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn016.png (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn016.png)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn017.png (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn017.png)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn018.png (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn018.png)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mirainikki_02_052.jpg (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mirainikki_02_052.jpg)
http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn10.jpg (http://i71.photobucket.com/albums/i146/Mr-Crispy/Mirai%20Nikki/mn10.jpg)
Sounds sick... in an appealing way