The command-line utility sysdiagnose can be triggered by pressing Cmd+Opt+Ctrl+Shift+Period, and it may take a few minutes to complete. When ready, the output will automatically be revealed in a Finder window (or it can be manually retrieved from /var/tmp).

What sysdiagnose Collects:
A spindump of the system
Several seconds of fs_usage ouput
Several seconds of top output
Data about kernel zones
Status of loaded kernel extensions
Resident memory usage of user processes
All system logs, kernel logs, opendirectory log, windowserver log, and log of power management events
A System Profiler report
All spin and crash reports
Disk usage information
I/O Kit registry information
Network status
If a specific process is supplied as an argument: list of malloc-allocated buffers in the process’s heap is collected
…

Source: Mac OSX Hints