Pretty amazing deal, not sure if this is even advertised or supposed to happen, but right now you can get LEGO Rock Band for 50% off on XBOX 360 only. Then add an AC / DC track pack (Wii, PS3, or XBOX 360). That will show up in the cart for FREE.
You can also use coupon code
SAVER for free shipping, so just add Rock Band Revolution for $5 to qualify.
When all is said in done, you get all 3 games for $30 shipped. Just click the deal link to start the process with Lego Rock Band.