Open a terminal (Applications -> Accessories -> Terminal in Ubuntu 10.04) and type:

less /proc/cpuinfo

This gives a lot of information. Look for the ‘model name’ entry the top of the list.

For example, here are the first several lines of my /proc/cpuinfo:

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU N270 @ 1.60GHz
stepping : 2
cpu MHz : 800.000
cache size : 512 KB
…

Press the spacebar to go down a ‘page’ and ‘q’ to quit.

Open a terminal (Applications -> Accessories -> Terminal in Ubuntu 10.04, for example). Typing:

find . -mtime -1 -print

will find files in the current directory that have been modified in the past 24 hours. The ‘.’ can be replaced with another directory.

Thanks to My Digital Life for the information – this site gives more information and other options.