[Show and Tell] Graph of Bukkit Server Load Over 4 Days

No major questions here, but I made a graph of my Bukkit server's load over 4 days, and it looks pretty interesting. If anyone knows what causes the large spikes/changes in the patterns, that would be cool to know.
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There appears to have been some sort of memory leak from 10jul 8pm to 11jul 8pm, but it seems to have resolved itself. A lot of the spikes/changes in usage align, and I'm curious what causes these changes.

Lugnuts

 

What is along the Y axis and what did you make this graph with, very interesting. Some cool spikes, maybe players running around? restarts would explain the drops, very cool!

 

You've got 6 unlabeled curves on there. WTF do they represent?

 

Bobcat00: The labels are in the top right. (From top to bottom in the graph: Mem. Max, Mem Allocated, Mem Used, Threads, CPU%, Players)
aidan573: The Y axis is just a log scale with numbers, I couldn't really find a better way without splitting up the graph.