There was an activity log last night, but stupid me accidentally deleted it. Some of the logged data had comcast or dynamic.dsl in the source DNS field. If I clicked the "more info" option, zonealarm told me it could just be background noise, and not to worry.
I did have frostwire & limewire on my computer. But neither was running at the time of the LAN activity. I verified this through the task manager. I don't think these programs were doing it b/c my complete/incomplete downloads weren't showing as modified during this activity. Plus, zonealarm didn't alert me to them trying to access the internet.
Does anyone have any suggestions? And could limewire/frostwire have been somehow downloading data?