I got a friendly letter from the State of Washington Department of Revenue that I'm delinquent on my WA business tax return for 2005. Oops! I figured they'd send me something. After filing two "seriously, I didn't make any money" reports in a row, I thought they said that I didn't have to file taxes anymore until that changed. Apparently they said that I only had to file once a year.
Luckily, the penalty for failing to pay business taxes in WA is 5-15% of tax owed, and we all know what zero times a number is. They even point that out on the friendly warning letter.