Via FARK, there was a note on the top ten videos of robots by New Scientist: http://www.newscientist.com/popuparticle.ns?id=in124#faq3
At number 4, we have the spherical security guard:
http://www.rotundus.se/press.php?lang=en
Looks familiar:
http://www.sadgeezer.com/html/Reviews+index-req-showcontent-id-501.html
There is no escape, we are all prisoners; time to find who is number 1… 
I am not a number! I am a free man!
Number 2: BWA HA HA HA HA!!!
(drops dead)
Number 2 is scooped by Roomba and Scooba, the actual “number 2” robots in the list. 
And just like in the show, a new number 2 appears right away.
“Why did you think a big balloon would stop him?”
“Shut up! That’s why!”
/Simpsons