Doing my bit to perpetuate the history meme:

$ history|awk '{print $2}'|sort|uniq -c|sort -rn|head
    116 make
     76 vim
     63 ./mandelbrot
     44 cd
     27 ./kill.sh
     22 sudo
     11 ssids
     11 ll
     10 man
      9 ..

Notes

• mandelbrot and kill.sh are for a particularly fiendish Concurrent Systems assignment.
• ssids is a quick one-liner to list wireless access points: sudo iwlist scan 2>/dev/null | grep SSID | sed -r 's/^\s*ESSID:"([^"]+)"/\1/' | sort | uniq
• alias ll='ls -aFhlv'
• Perhaps the laziest alias in my collection: alias ..='cd ..'