In Team Foundation Server today, it is only possible to start a build on a team build server that is not already running a Team Build. If the server is busy it is not possible to queue-up the build we want to make, which means that we not only need to wait the time the build takes to have the result, we must also wait until the build server is free in order to trigger the build. On a busy server, running continuous integration builds, it can actually be a problem to get a build started.
So in order to come around this problem we've implemented a simple queueing process in TFSBuildLab so that any number of team builds can be queued and the server process will start the builds in priority when the server is available. And, yes, it is possible to remove builds from the queue too.