Friend Challenges are challenges you can receive or send to friends (i.e. “Beat my time around LA Downtown”). After a challenge is completed, an updated challenge can be sent back the original sender. These challenges go back and forth for as long as the players participate. A player needs to complete a race in the Single Player portion of Blur, before they can build Friend Challenges. If the player completes the objective, they are are given the option to create a Friend Challenge from their race result. Players receiving challenges don't need to unlock the cars and career events they don't have in order to play the challenges. Fan points are gained from completing friend challenges.
Blur will automatically fill in the blanks of the challenge, like altering the time to complete a circuit accordingly to what the player got rather than what the original race required. However, The challenges can be altered in many ways, such as limiting certain power-ups or requiring a certain amount of fan points.
A gold membership of Xbox Live is not required to send and receive Friend Challenges.