Madlib just released his excellent Four Tet-assisted album Sound Ancestors today, and Freddie Gibbs -- who has released two excellent albums with Madlib -- celebrated the album's release by recording freestyles over two of the album's tracks ("Dirtknock" and "Hopprock") from the back of an Uber. You can hear what is presumably a passenger and/or the driver laughing and cheering him on, and the whole thing is very fun. Check it out: