I have over 600 days worth of weblogs and I decided to play around with them a bit. Using GD [1] to handle the actual graphics, I made a graph [2] of accesses to my site over the past 600 days. The X-axis is in minutes, the Y-axis is days and I basically graphed a point for a hit (or hits) per minute of time.
I can get away with this since I don't receive that much traffic.
Some things are apparent immediately: vertical lines are repeat hits at the same time each day (the bottom of the graph shows an automated script the colocation facility runs to monitor the server), while a horizontal line indicates hits across an extended period of time in a single day.
I also had the program report back the number of hits per minute: it averages probably two or so per minute, but has a peak of 167 per minute.
Quite interesting.
[1] http://www.boutell.com/gd/