The good news is that you can! As Jono shared, we want to dogfood the core apps this month. The core apps can all be run on your ubuntu desktop, you don't need to flash a phone or tablet, and you don't even need to be running saucy (ubuntu development version). (Of course if you do have a phone, flash it and dogfood there if possible!)
To be fair, running and playing with the core apps is a lot more fun than eating actual dogfood, and it might even be healthier for you too :-p
Enter the core apps ppa. Just a quick command away and you can get access to all of the core apps. Ready?
EDIT: You also need the qt5 and ubuntu-sdk team ppa in order for the dependencies to work. Sorry!
sudo add-apt-repository ppa:canonical-qt5-edgers/qt5-proper
sudo add-apt-repository ppa:ubuntu-sdk-team/ppa
sudo apt-get update && sudo apt-get install ubuntu-sdk
sudo add-apt-repository ppa:ubuntu-touch-coreapps-drivers/daily
sudo apt-get update && sudo apt-get install touch-coreapps
This will install the ppa and all of the core apps. They should run just fine on your desktop.
So now what? Well, even without a phone you can dogfood the apps a little. Try them out. Use them. Find bugs and problems. See if they meet your needs (real or percieved) for usage. Everyone's needs and usage will be different, and thus this early feedback is important to get into the hands of the developers.
Find a bug? See a potential missing feature? Check out the dogfooding page for bug reporting links and instructions as well as blueprints showing work items and status for features. Happy Testing err, Dogfooding!