The first wave of Xbox 360 games with a substantially reduced price are available.

Several stores reduced prices of selected games to $39.99.
Circuit City is more aggressive and has reduced prices on a couple of games below $30:

Madden NFL 2006 sells for $27.99 (in-store only)

Tiger Woods PGA Tour 2006 sells for $27.99 (only online)

NBA Live 06 sells for $29.99 (only online)

Full Auto sells for $29.99 (in-store only)

Burnout Revenge sells for $29.99 (in-store only)
More details on Circuit City (Thanks Dan A.)

Amazon.com or Gamestop cannot beat Circuit City on those prices. Guess this sale will not last long.