Rock Band DLC (Tuesday; * means you can buy pro guitar/bass for an extra $1) Queen Extravaganza Pack 01 - Hammer to Fall* - Keep Yourself Alive* - Now I’m Here* - Play the Game* - Tenement Funster* - We Are the Champions (RB3 version) - We Will Rock You (RB3 version)
Queen RB3 Enhanced Pack - I Want It All (RB3 version)* - I Want To Break Free (RB3 version)* - Killer Queen (RB3 version)* - One Vision (RB3 version)* - Somebody To Love (RB3 version)* - Under Pressure (RB3 version)*
The free games are part of some Doritos contest. Through the Xbox dashboard, you can vote for your favourite.
Rock Band Network DLC (Wednesday) – A Day To Remember – Have Faith In Me (160 MSP) – The Break Down – So Fine (80 MSP) – Broken Equilibrium – November (80 MSP) – Cate Sparks – Angels We Have Heard On High (160 MSP) – D Money Pros – Saw Down (He Knows) (80 MSP) – Heaven Shall Burn – Endzeit (160 MSP) – Hellfire Society – Run Rabbit Run (160 MSP) – The Last Good Year – Lipstick Cigarette (80 MSP) – Mike Phirman – Lollytown (80 MSP) – Portugal. The Man – Do You (160 MSP) – Rosaline – Model Ships (160 MSP)
Lara Croft Guardian of Light DLC (Wednesday) - A Hazardous Reunion (400 pts)
Costume Quest DLC (Wednesday) - Grubbins on Ice (400 pts)
From what I understand, they're no longer hard to find as stores are getting new shipments every week. I sold mine a few weeks ago on eBay once I decided I didn't have time to play anymore, and I could barely recoup how much I paid for it at launch.