VMJuggler
VMjuggler is an application I wrote to use during demonstrations. The program is quite simple, it connects to VirtualCenter 2.x and you can select a VM and 2 hosts. After selecting this you can start the juggler and the VM will be moves every 10 seconds between the hosts. The fun thing to do of course is while this is going on with the virtual machine is to run parallel a load generation program against your VM to see how much it is impacted. It also keeps a counter to see how many vmotions have been taking place.
First one to get 1 million vmotions and send me a screenshot (no cheating) will get a small price 
Feel free to send any bugs or suggestions to the.anykey@gmail.com