World TB-303 Appreciation Day is celebrated annually on March 30 to honor the Roland TB-303, a legendary bass synthesizer that significantly influenced the development of electronic music. Initially marketed as a computerized bass machine, it was designed by engineer Tadao Kikumoto to replicate the sound of an electric bass guitar. Although it was initially deemed a failure and discontinued, its affordability allowed it to reach many emerging electronic music producers. The TB-303 gained prominence through its use by the Chicago-based acid house group Phuture, who created the seminal track "Acid Tracks," credited with defining the acid house genre. Today, the original TB-303 is highly sought after, often selling for over 1,000 pounds, and it remains a staple for DJs worldwide. Celebrations typically involve showcasing music created with the TB-303 and encouraging people to dance and appreciate its enduring impact on dance music.