The Baltimore Ravens (NFL)
Cost of naming rights:
$5.3 million a year
During the dot-com era, there was no better way to say "this company won't be here in a decade" than to put its name on a stadium.
For those of you who don't remember that period or blocked out the losses with some extraordinarily selective amnesia, PSINet was one of the nation's first Internet service providers. In the spirit of the times, PSINet bought itself some stadium naming rights in 1999 and just waited for the money to start flowing in.
Two years later, and just after the Ravens won their first Super Bowl, PSINet went bankrupt and its stadium signage was thrown into the same scrapheap as the Pets.com sock puppet.
eventually took over the rights in 2003.