From laundr.us:

jason@jubunt:~/dev/bridge$ history | awk '{print $2}' | awk 'BEGIN {FS="|"} \ 
{print $1}' | sort | uniq -c | sort -nr | head -10
     98 rake
     89 svn
     56 cd
     46 ls
     17 sudo
     17 ssh
     15 more
     15 ./bridge_dev_wmii.sh
     13 irb
     11 wget