how to make money while traveling?

I went backpacking in Europe for about 2.5 months during the summer of 07, right after I graduated from ASU. While staying with a friend in Lagos, Portugal, I got a job at a local bar called 'Inside Out Bar', and was paid cash under the table. I worked for a total of 8 nights, and most of us at Inside Out were foreigners without work visas, but we catered to tourists and the bar needed English speakers. This was a common situation amongst bars in Lagos, and I'm sure this sort of things happens at bars and nightclubs all over Europe. Anway, I drank for free everyday and made a little bit of money. I highly recommend it.