Che Guevara, what did he do that made him so famous/infamous?

Most people who seem to admire him don't know very much about him. He's become a cultural icon for something countercultural, so when you see people wearing t-shirts with his image on them, they're primarily doing so in the same spirit that the same types of idiots will wear Anarchy t-shirts (despite the fact that it's a very bad idea) or Free Love t-shirts (yes, ual promiscuity is also a poor choice). These types of people love to be noticed and especially like being "different." They also like pissing people off just a little bit, so don't do too much to make them feel like they've accomplished something. The only really good things going for him is some help from Nelson Mandela, who spoke highly of him, and his early life's activity that included working as a male nurse and volunteering at a leprosarium.