Block B is my second favorite band, and interestingly they get a lot of comparisons to Big Bang. I can see why this is, but I definitely think Block B has their own charm and style.
Again, to make it faster for me I am including an excerpt of Wikipedia on Block B with a couple of additional notes from me.
Block B (Hangul: 블락비) is a South Korean group created by Cho PD under his label Brand New Stardom. On April 15, 2011, they made their debut on KBS Music Bank with their promotional single, "Freeze!" ("그대로멈춰라!"). The group consists of seven members: Zico (Woo Jiho) the leader, Lee Taeil, B-Bomb (Lee Minhyuk), Ahn Jaehyo, U-Kwon (Kim Yukwon), Park Kyung rapper, and P.O (Pyo Jihoon) rapper. The members of Block B have dancing, rapping, composing, and singing experience.
They are a newer band with not a lot of music or videos out, but what they do have is definitely addictive. Narina and Nillili Mambo in particular will refuse to leave your head for weeks. The videos are great too. They’ve also done several variety shows like MTV Match Ups. Their recent album named Blockbuster released in 2012, was able to reach #10 on the "Billboards World Album Chart". In this new album, the band members were heavily involved in writing and producing, and I think that individuality shows in the music. I look forward to anything they do in the future.