Right now the log is one full log. Not sure of any advantage to parsing it into separate logs by day other then it'd be easier to manipulate and work with. But if needed I could probably work something up.
I have daily log files going back to the end of july 2010 over
here. Logs are generated by GIGO, and lines prefixed with [nolog] are automatically redacted. You're welcome to steal them for your own uses.
Logs are standardized as follows:
Filenames: #computerhope.YYYY-MM-DD.log
internal date/timestamp structure: YYYY-MM-DDTHH:MM:SS <nick> MESSAGE or *** NICK join/part/quit