You can start up your own small network by following these instructions > http://maidsafe.net/maidsafe-examples/en/001_network_setup/local_network_setup.html
I just noticed this needs updated as the options have changed slightly - as David said it has been a mad few weeks 
I think you will still be able to follow it and start a local testnet - if not shout. In itself (without a visualiser session and testnet) just now this might seem a little underwhelming. You can build and run tests like network_test_nfs or network_test_api. Or if you want to assist with general testing you can run Experimental tests that report to http://dash.maidsafe.net/index.php?project=MaidSafe like Exper< project > e.g. ExperCommon from your build folder.
3 Likes