• Solid Gold, Baby! - Gold star any song. - 25
  
• Flawless Fretwork - 100% a song on Expert guitar. - 25
  
• Flawless Drumming - 100% a song on Expert drums. - 25
  
• Flawless Singing - 100% a song on Expert vocals. - 25
  
• Flawless Groove - 100% a song on Expert bass only using up-strums. - 25
  
• Flawless Guitar Solo - 100% a guitar solo using only the solo buttons. - 20
  
• Flawless Guitar Solo - 100% a guitar solo using only the solo buttons. - 20

See the full list here http://xbox360.ign.com/articles/897/897508p1.html