The longest active sellout streak in pro sports is...

[Mephistopheles]

...the Dayton Dragons?

 

http://sportsillustrated.cnn.com/multimedia/photo_gallery/0704/gallery.hottest.tickets/content.10.html

[karenmac]

yep, I can remember Nate mentioning on the radio when the Chiefs were there early last season. It was cold and rainy, but the stands were packed. If I remember correctly, they're also affiliated with the Reds, so having the parent team so near (and the fan base to draw from) doesn't hurt either. They even have their own Dragon-mobile bus that takes them around.