Beloit and Janesville firefighters are called out to more than dozen fires over the weekend.  Beloit responded to a porch fire in the 1200 block of Summit about midnight Saturday after someone left a grill unattended.  About 6:00 a.m. Sunday firefighters dealt with a smoldering fire in a basement in the 700 block of Grant Street.  Firefighters responded to the 200 block of Poole Court for a dumpster fire just before noon Sunday.  About 1:00 p.m. Sunday firefighters were called to the 2200 Block of Burton for mulch on fire.  The alarm sounded again about midnight Sunday for a car fire at the Staples Distribution Center on Colley Road.  Beloit firefighters also battled about a half dozen grass and brush fires over the weekend.  Janesville firefighters responded to at least eight brush fires on Saturday alone.  Two fires were considered significant.  Those were at County O and Highway 14, and Mineral Point and Pahl Road.  Officials say the most common cause was burning piles used in previously days reignited. No one was reported hurt.  The Clinton Fire Department also called in mutual aid for a barn fire in the 7000 block of Carvers Rock road about 5:00 p.m. Saturday.