go browse some random shady pron on IE (turn your security setting to low) and that should do it for ya
also google might be able to help, I know there are a few viri you can download to "test" your system.
install some random programs that scream of spyware (like kazaa, office, exeem)
edit: after looking at eclair, I think that it's intent is to be non malicious, but to test the programs, so if your intent is to slow the system down that won't work...
also, if you can wait a week or two I can do a hdd image of one or 2 teenagers unmonitored/unspywared machines, those seem to be good when it comes to this.