Today is 24 February, which in European date formation is 24/2. I doubt that EBM day is widely recognised because it is a tiny sub-genre of music and definitely not as well known as pi day or Star Wars day or even Fulham 5 day. EBM is Electronic Body Music a genre of electronic music that combines elements of industrial music and synth-punk with elements of dance music [Wikipedia]. I only found out about EBM because of seeing Rammstein at Wembley Arena in around 2009.
If you are wondering why EBM day is the 24 February then you only need to understand that one of the biggest bands in the movement is called Front 242. I’ve seen them at M’era Luna and I’ve got a load of their albums. I prefer some other bands but I’m very happy to have 242 as the lead proponents of EBM and the use of their name to create EBM day.