During Paul's journey through Asia Minor (Turkey) and Greece, he spent a long time in specific places - two years in Ephesus alone. While he was there, he would have worked his trade, making tents. The people of Ephesus, believing so strongly in the good news he was preaching about Jesus, people began using Paul's sweaty rags to heal people. Exciting, but also weird.
As well as the extraordinary miracles Paul and others performed in the name of Jesus, in this passage we see the most extraordinary miracle: Crowds of people repenting from their sorcery, burning their spell books, worth over 100 years wages.