If you have fast Internet connection, you can give the latest KOffice 1.5 a try, without the need to install Linux and/or download any other programs. You can even do it from normal Windows desktop. Just go to CosmoPOD, register (free) and launch your KDE with KOffice 1.5.
The speed may not be the fastest (e.g. compared to running it locally), but surely enough to check out those brand new features mentioned in KOffice 1.5 Tour.
Note 1: I'm not affiliated with CosmoPOD.
Note 2: "no-install" is a bit incorrect, since you may need NX client. But I hope you get the point.