I attended a Independiente Medellin game and it was awesome ! Before and after the game you hang around with locals and the guides at a little shop where you can get facepaintings and buy beers. They also give free Aguardientes shots to you. The guides are super friendly and can answer all your questions.
The atmosphere at the game is just awesome, it is even a nice experience if you are not the biggest football fan. You get really experience the real Colombia !
Christoph Kuehn