I don't have any kind of malware that I really like. If I had to choose some category, and I know the file in the video is not really a virus, but something that does some funny things like this one:
It's just fun to watch this in a virtual machine and to see your cpu is burning down
Note: if you REALLY crave malwares, go to KernelMode.info and make an account, then go along the link like this one, as venustus said: KernelMode.info • View topic - Rogue Antimalware (FakeAV, 2011 year)
(Note: This link shows Navashield sample on the page 5, and there are some gems on pages other than 5.)
To moderators: This is NOT a direct link to malware file. So, please do not remove this link.
For more in-programmer's-view perspective on those, check out fine work from Xylitol from that forum here: XyliBox
...And from here, from another awesome author: http://krebsonsecurity.com/