Nothing But Head 100gs- Finish The Campaign with every kill being a headshot on normal or up difficulty. You Got Some Blue There 100gs- Finish The Campaign with every kill being a stick by a plasma grenade. Best There Is 50gs- Complete all levels of Campaign ,Firefight and all achievments in multiplayer Stop Playing 5gs- Play for 2 weeks. Sneaky, Sneaky, Sneaky 50gs- Complete The Campaign without alerting more than 30 of the covenant and/or without killing more than 15 of the covenant I think some of these are fairly well thought out. [Edited on 06.13.2009 5:32 PM PDT]