The 2002 SIGCOMM Workshop on Educational Challenges for Computer Networking [Kur02a] exposed many issues related to teaching computer networking with the need for a laboratory in parallel with lecture a recurring theme. We have created TinkerNet, a low cost (mostly throw-away PCs), laboratory environment for networking experiments focused on the Build-Your-Own-Stack (BYOS) activity. This paper describes the hardware and software environment that is TinkerNet together with a set of student experiments. We discuss our plans for formal assessment to determine how the addition of laboratory experiments affects student learning. Finally the status and availability of TinkerNet is noted. 1 Overview The 2002 SIGCOMM Workshop on Educational Challenges for Computer Networking [Kur02a] exposed many issues related to teaching computer networking with the need for a laboratory in parallel with lecture a recurring theme. We, (Computer Science at Harvey Mudd College and Computer Science at Universi...